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Polybrominated diphenyl ethers (PBDEs) in chicken eggs and cow milk around municipal dumpsites in Abuja, Nigeria
Abstract
Polybrominated diphenyl ethers (PBDEs) are used as flame retardants in electronic equipment, as polymers in vehicles or construction, and in textiles. These additive flame retardants are emerging pollutants in Africa, released by the non-environmentally sound disposal of consumer products, often imported as secondhand, that have increasingly reached their end-of-life in the last decade. In Nigeria, which is a major receiver of e-waste and secondhand cars, there is a dearth of information regarding the levels of PBDEs in the environment, biota, and food. Thus, this study was designed to investigate the PBDE contamination of food samples of animal origin (chicken eggs and cow milk) around municipal waste dumpsites and background areas in Nigeria, to elucidate the role of dumpsites as potential sources of PBDE pollution and exposure in the country. Biological samples were collected over two years from two municipal waste dumpsites in Abuja. Fifty-six samples each of free-range chicken eggs and cow milk were collected. Control samples were collected approximately 5 km away from the dumpsites. After extraction and clean-up, the levels of POP-PBDEs listed in 2009 (major congeners of tetraBDE to heptaBDE), plus BDE-28 (Σ 7 PBDEs) were determined using GC-ECD. Data were analysed using descriptive statistics, t-test at α 0.05 . Levels of Σ 7 PBDEs (ng/g lipid weight (lw)) in chicken eggs at the two study sites ranged from 262.3 to 313.4 (ng/g lw), more than one order of magnitude higher than those at the control site in a village near the dumpsites (14.9 ± 3.73 ng/g lw), and two and more orders of magnitude higher compared to PBDE levels in these products in industrial countries and Nigerian supermarkets. Median PBDE levels in cow milk from the two dumpsites were 49.1 and 81.5 ng/g lw, respectively, considerably higher than levels in other studies. Proper disposal methods of waste polymers containing PBDEs such as co-incineration in BAT cement kilns and plastic recycling with separation is urgently needed in Nigeria and other parts of Africa, to prevent open burning as well as crude recycle to reduce PBDE levels in the environment and human food.
... The transfer of HBCDD to eggs due to chickens picking flame retarded polystyrene has been documented (Hiebl and Vetter 2007). Monitoring data have shown that chicken eggs and milk produced around landfills in Nigeria contain high levels of PBDEs (Oloruntoba et al. 2019). House crickets can accumulate PBDEs after feeding on PUF for 28 days (Gaylor et al. 2012). ...
... Indigenous peoples in the Arctic have an especially high exposure through the consumption of their traditional foods (AMAP 2017). Near dumpsites in developing countries, human exposure to PBDEs is known to occur via food, such as eggs and milk (Oloruntoba et al. 2019;Petrlik et al. 2021). For PAHs, the major source of exposure is through food consumption and the dietary intake of PAHs can be up to 22.5 µg/day (Domingo and Nadal 2015). ...
... PVC as well as brominated and chlorinated flame retardant-containing plastics are major contributors to the release of PCDD/PCDFs and PBDD/PBDFs (Ikeguchi and Tanaka 1999;Shaw et al. 2010;Gullett et al. 2010) and the associated environmental contamination and human exposure (Tue et al. 2013;Weber et al. 2018c). Eggs and milk around dump sites and recycling sites where plastics were burnt in developing countries contain high levels of POPs such as PBDEs and SCCPs (Labunska et al. 2014;Zeng et al. 2018;Adu-Kumi et al. 2019;Oloruntoba et al. 2019, Oloruntoba et al. 2021. ...
https://www.unep.org/resources/report/chemicals-plastics-technical-report
The report provides state of knowledge on chemicals in plastics and based on compelling scientific evidence calls for urgent action to address chemicals in plastics as part of the global action on plastic pollution.
Overview of the report:
The “Chemicals in Plastics: A Technical Report” aims to inform the global community about the often-overlooked chemical-related issues of plastic pollution, particularly their adverse impacts on human health and the environment as well as on resource efficiency and circularity. Based on compelling scientific evidence, it further highlights the urgent need to act and outlines possible areas for action. It also aims to support the negotiation process to develop the instrument on plastic pollution based on United Nations Environment Assembly resolution 5/14. The report outlines a set of credible and publicly available scientific studies and initiatives focused on chemicals in plastics and the science-policy interface.
The report was developed by UNEP in cooperation with the Secretariat of the Basel Convention on the Control of Transboundary Movements of Hazardous Wastes and Their Disposal, the Rotterdam Convention on the Prior Informed Consent Procedure for Certain Hazardous Chemicals and Pesticides in International Trade, and the Stockholm Convention on Persistent Organic Pollutants, with lead authors from the International Panel on Chemical Pollution, as well as contributions from key experts.
Some key findings:
Based on the latest studies, more than 13,000 chemicals have been identified as associated with plastics and plastic production across a wide range of applications.
Ten groups of chemicals (based on chemistry, uses, or sources) are identified as being of major concern due to their high toxicity and potential to migrate or be released from plastics, including specific flame retardants, certain UV stabilizers, per- and polyfluoroalkyl substances (PFASs), phthalates, bisphenols, alkylphenols and alkylphenol ethoxylates, biocides, certain metals and metalloids, polycyclic aromatic hydrocarbons, and many other non-intentionally added substances (NIAS).
Chemicals of concern have been found in plastics across a wide range of sectors and products value chains, including toys and other children's products, packaging (including food contact materials), electrical and electronic equipment, vehicles, synthetic textiles and related materials, furniture, building materials, medical devices, personal care and household products, and agriculture, aquaculture and fisheries.
Chemicals of concern in plastics can impact our health and our environment: Extensive scientific data on the potential adverse impacts of about 7,000 substances associated with plastics show that more than 3,200 of them have one or more hazardous properties of concern.
Women and children are particularly susceptible to these toxic chemicals. Exposures can have severe or long-lasting adverse effects on several key period of a women’s life and may impact the next generations. Exposures during fetal development and in children can cause, for example, neurodevelopmental / neurobehavioural related disorders. Men are not spared either, with latest research documenting substantial detrimental effects on male fertility due to current combined exposures to hazardous chemicals, many of which are associated with plastics.
Chemicals of concern can be released from plastic along its entire life cycle, during not only the extraction of raw materials, production of polymers and manufacture of plastic products, but also the use of plastic products and at the end of their life, particularly when waste is not properly managed, finding their way to the air, water and soils.
Existing evidence calls for urgent action to address chemicals in plastics as part of the global action on plastic pollution, to protect human health and the environment, and transition to a toxic-free and sustainable circular economy.
UNEP acknowledges the financial support from the Government of Norway, the Government of Sweden and the Government of Switzerland, for the development of the report.
... Higher concentrations of PBDEs were reportedly found in the top layer of soil than in the layers of soil below, indicating either atmospheric deposition or upward mobility of PBDEs in soils to enrich the top layer. Oloruntoba et al. reported excess concentrations of ∑ 7 BDEs (110-370 ng/g) in soil samples collected from Karmo and Anjanta dumpsites in Abuja, Nigeria [35] . These concentrations were reported to significantly exceed the control sites. ...
... A summary of the concentrations reported on human/biological samples is presented in Table 2, while the details of individual compounds are shown in Supplementary Tables 2-6. In two studies conducted in 2019 and 2021, high levels of PBDEs were reported from selected plants (∑ 7 BDEs 8.5-61 ng/g dw) [35] , free-range eggs (∑ 7 BDEs 190-370 ng/g lipid wt.) [50] and cow milk samples (∑ 7 BDEs 33-100 ng/g lipid wt.) [50] collected from Karmo and Anjanta dumpsites, Abuja, Nigeria. Oloruntoba et al. reported that these concentrations significantly exceeded those of the control samples [35,36] . ...
... In two studies conducted in 2019 and 2021, high levels of PBDEs were reported from selected plants (∑ 7 BDEs 8.5-61 ng/g dw) [35] , free-range eggs (∑ 7 BDEs 190-370 ng/g lipid wt.) [50] and cow milk samples (∑ 7 BDEs 33-100 ng/g lipid wt.) [50] collected from Karmo and Anjanta dumpsites, Abuja, Nigeria. Oloruntoba et al. reported that these concentrations significantly exceeded those of the control samples [35,36] . ∑ 7 BDEs were reported to vary between plant roots (25-61 ng/g dw) and shoots (8.5-32.2 ...
Per- and polyfluoroalkyl substances, chlorinated paraffins, brominated flame retardants, polychlorinated biphenyls and mirex are regulated under the United Nations Environment Programme’s (UNEP’s) Stockholm Convention on Persistent Organic Pollutants (POPs) intended for the eradication of hazardous contaminants in the environment. There is also a major concern for organophosphate esters and specific alternative or novel brominated flame retardants. To date, no evidence exists that major producers of these chemicals occur on the African continent. They are understood to find their way into African environments through the import of commercial products, in particular products with second-hand value and short lifespans, which may enter waste streams in a relatively shorter period. To further understand the current levels of these selected contaminants in African waste streams, existing documents capturing various African waste stream compartments for the above outlined targeted contaminants were gathered from an exhaustive literature review. Key factors influencing the transfer of contaminants from waste or elevated concentrations of contaminants in African waste streams are associated with the nature and/or sources of contaminants, volume of contaminants or waste in relation to the capacity of treatment plants/landfills, condition or age of treatment plants/landfill geomembrane liner, model adopted for contaminants removal and treatment procedures for collected sludges or leachates. Evidence from the selected studies indicates substantial POP contamination in African landfills and dumpsites, wastewater effluents/sludge and human/biological samples around dumpsites and landfills. Unfortunately, the continent has inadequate infrastructural capacity to adequately handle POP in the waste streams. This review provides recommendations and suggestions for future studies.
... Karmo and Anjanta Landfill Facilities) operated since 1995 and 2003, respectively. Details on the landfill locations are published in our former study (Oloruntoba et al., 2019) and a map is included in the Supporting Information Figure S1. Scavengers are screening the waste on the dumpsites for recyclables, including waste products containing metals such as electrical and electronic equipment (EEE), certain polymers and wood, among others. ...
... 13 C-labelled PBDE standards and analytical grade solvents were purchased from international companies and have been described in our former publication (Oloruntoba et al., 2019) and details are included in the Supporting Information S1. ...
... Analyses for seven PBDE congeners were carried out. The analyses of PBDEs were performed following methods described by Adegbenro et al. (2011) with minor modifications as described in our former study (Oloruntoba et al., 2019) and detailed in the Supporting Information S2. ...
Polybrominated diphenyl ethers (PBDEs) are listed as persistent organic pollutants (POPs) in the Stockholm Convention. It has been established that PBDEs may be released into the environment during improper handling and disposal of e-waste and other products containing PBDEs that is prevalent in developing countries. This research work assessed the status of PBDE contamination at dumpsites in Nigeria. Soil and edible plant samples were collected from the dumpsites and control sites for analysis. The concentrations of ∑7PBDE in the topsoils around the dumpsites at 0-15 cm depth ranged from 112 to 366 ng/g dry weight (dw) while that of the topsoil of the control site 500 m from the dumpsite ranged from 26.8 to 39.7 ng/g dw. These high concentrations stem likely from open burning of waste including electronic waste on the landfills. Plant samples (bentgrass, spinach, tomatoes, pumpkin and sweet potatoes) around the dumpsites were found to be contaminated by PBDEs with levels ranging from 25.0 to 60.5 ng/g dw in plant roots and from 8.45 to 32.2 ng/g dw in plant shoots for ∑7PBDE. This suggests that consumption of vegetables by humans and ingestion of contaminated soils and feed by chickens and cows can transfer PBDEs into the human food chain around the dumpsites. The comparison of PBDE levels in soils and the PBDE levels in chicken eggs from the former study indicate that PBDE levels in the soils are sufficient to explain the levels in the chicken eggs with a reasonable carry-over rate for PBDEs of 0.28 on average. The PBDE contamination in the soil was sufficient to result in a relevant exposure of humans via accumulation in eggs. The study shows that a better management of end-of-life products containing PBDEs is needed to reduce PBDE exposure risk in Africa.
... Humans' exposure to PBDEs is through ingestion of food (dietary intake and consumer products), dermal contact, air and dust inhalation (Oloruntoba et al., 2019;Sahlström et al., 2015;Trudel et al., 2011), where their comparative influences to total exposure show a discrepancy by sex, age, geographical region, and congener (Sahlström et al., 2015;Trudel et al., 2011). Some undesirable impacts of POPs and their metabolites in humans include immunosuppression, neurotoxicity, endocrine system damage, carcinogenicity, and reproductive dysfunction (Oloruntoba et al., 2019;Ontiveros-Cuadras et al., 2019;Parry et al., 2018). ...
... Humans' exposure to PBDEs is through ingestion of food (dietary intake and consumer products), dermal contact, air and dust inhalation (Oloruntoba et al., 2019;Sahlström et al., 2015;Trudel et al., 2011), where their comparative influences to total exposure show a discrepancy by sex, age, geographical region, and congener (Sahlström et al., 2015;Trudel et al., 2011). Some undesirable impacts of POPs and their metabolites in humans include immunosuppression, neurotoxicity, endocrine system damage, carcinogenicity, and reproductive dysfunction (Oloruntoba et al., 2019;Ontiveros-Cuadras et al., 2019;Parry et al., 2018). BDE-47, BDE-99, and BDE-209 apply genotoxic and cytotoxic impacts and play an acute role in the destroying DNA, down-regulation of oxidative stress, and the associated gene expression in bronchial epithelial cells. ...
This study investigates the pollution of Markman stormwater runoff, which is a tributary to Swartkops River Estuary. Solid-phase and ultrasonic extraction methods were utilized in the extraction of water and sediment samples, respectively. The pH of the sampling sites was above the EU guideline. The ranges of concentration of \(\Sigma_{6}\)PBDE obtained in water and sediment samples for all the seasons were 58.47–1357 ng/L and 175–408 ng/g, respectively. Results also showed that BDE-66 was the dominant congener, specifically in the industrial zone, where its concentrations ranged from 2 to 407 ng/g in sediment. Consequently, the high concentration of BDE- 66 in the sediment of stormwater calls for concern. Penta-BDE suggests potential moderate eco-toxicological risk, as evident in the calculated risk assessment. The result showed possible photodegradation along the contaminant's travel time, as only 7% of the PBDE was detected at the point of entry into the Swartkops River Estuary. Markman stormwater may be contributing heavily to the pollution load of Swartkops River, as evident in the alarming concentrations of PBDEs obtained. The industries at this zone should eliminate the contaminants before discharging their effluents into the canal.
... Studies on POPs such as brominated flame retardants (BFRs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs) organochlorine pesticides (OCPs) and hexabromocyclododecanes (HBCDs) in different matrices have been carried out in Africa (Asante et al. 2011;Babayemi et al. 2015;Odusanya et al. 2009;Oloruntoba et al. 2019;Sindiku et al. 2015;Mansour 2009;Nkabinde et al. 2018;Adu-Kumi-Jonathan et al. 2019;Vaccher et al. 2020;Katima et al. 2017;Sibiya et al. 2019). However, there is limited information on CP studies in different matrices, with the exception of the studies by Adu-Kumi-Jonathan et al. (2019), Brits et al. (2020) and Möckel et al. (2020). ...
... Open burning of solid waste is also a common practice in most African countries inclusive of polymeric products (Babayemi et al. 2014). As a result of lack of effective solid waste management, mixed wastes including polymers end up in dump sites where they are burnt, resulting in the release of POPs into the environment (Oloruntoba et al. 2019). Studies have further shown that depending on the type and use, polymeric products contain a wide range of additives such as plasticizers, flame retardants, antioxidants, acid scavengers, light and heat stabilizers, lubricants, pigments, antistatic agents, slip compounds and thermal stabilizers which are used for various purposes (Geyer et al. 2017;GIA 2008;Rajaram 2009;Hahladakis et al. 2018;UNEP 2019b). ...
Chlorinated paraffins (CPs) have been applied as additives in a wide range of consumer products, including polyvinyl chloride (PVC) products, mining conveyor belts, paints, sealants, adhesives and as flame-retardants. Consequently, CPs have been found in many matrices. Of all the CPs groups, short-chain chlorinated paraffins (SCCPs) have raised an alarming concern globally due to their toxicity, persistence and long-range transportation in the environment. As a result, SCCPs were listed in the Stockholm Convention on Persistent Organic Pollutants (POPs) in May 2017. Additionally, a limit for the presence of SCCPs in other CP mixtures was set at 1% by weight. CPs can be released into the environment throughout their lifecycle, therefore, it becomes crucial to assess their effects in different matrices. Although about 199 studies on SCCP concentration in different matrices have been published in other continents, however, there are scarce/or limited studies on SCCP concentration in Africa, particularly on consumer products, landfill leachates and sediment samples. So far, published studies on SCCP concentration in the continent include, SCCPs in egg samples, e-waste recycling area and indoor dust in Ghana and South Africa, despite absence of any production of SCCPs in Africa. However, there still remains a huge research gap in the continent of Africa on SCCPs. Consequently, there is need to develop robust SCCPs inventories in Africa since the Stockholm Convention has already developed guidance document in this respect. This review, therefore, examines the state of knowledge pertaining to the levels and trends of these contaminants in Africa, and to further provide research gaps that need to be considered in order to better understand the global scale of the contaminant.
Key words: POPs, CPs, SCCPs, matrices, Africa
... Data on the PBDE concentrations in milk are limited to the product from cows (Oloruntoba et al., 2019;Pardo et al., 2020;Parolini et al., 2012;Poma et al., 2016) or milk without an indicated origin species (Boucher et al., 2018;Chang et al., 2017;Chen et al., 2017;Fernandes et al., 2016;Rivi ere et al., 2014;Zacs et al., 2020;Zhang et al., 2013). PBDE concentrations are also available for different dairy products, and of them, data were reported most frequently for butter (Pardo et al., 2020;Rivi ere et al., 2014;Roszko et al., 2013;Schecter et al., 2010a;Uçar et al., 2011;Wojtalewicz et al., 2007). ...
... It is probably the result of the high usage of PBDE commercial mixtures in particular world regions, an example of which is North America which has utilized more than half the global production of PBDEs and 95% of the penta-BDE product (Shaw and Kannan, 2009). Thus far, the most polluted milk has come from cows grazing around municipal dumpsites in Nigeria (Oloruntoba et al., 2019). Interestingly, the concentrations of PBDE in milk from the theoretically unpolluted Alpine region were also higher than those in our results (Parolini et al., 2012). ...
Polybrominated diphenyl ethers (PBDEs) are widespread, persistent in the environment, and classified as global pollutants. Their presence has been confirmed in various types of food which adversely affect human health when consumed in sufficient amounts. Although milk has advantageous nutritional qualities and there are health benefits associated with its consumption, it could also contain toxic PBDEs. The aim of the study was the determination of the concentrations of ten congeners (BDE -28, -47, -49, -99, -100, -138, -153, -154, -183, and 209) in cow’s, sheep’s, and goat’s milk obtained from Polish farms and their determination in infant formula. A total of 103 samples of raw milk and infant formula were tested using an accredited high-resolution gas chromatography–high-resolution mass spectrometry method. PBDEs were detected in all analyzed samples, the highest concentration being found in sheep’s milk (11.9 ng g⁻¹ fat), and cow’s milk containing the least contamination. BDE-209 makes the predominant contribution to the sum of the ten congeners, constituting at least 38%. The profiles of PBDEs were dependent on the milk type and the differences between its varieties are discussed. The highest median concentration of the sum of ten PBDEs (0.473 ng g⁻¹ fat) was determined in infant formula, which was identified as an important source of infants’ exposure (5.48 ng kg⁻¹ b.w. day⁻¹ calculated based on P95 concentration). Milk is a source of PBDE in the diet; however, considered in isolation its consumption does not pose a risk to either adults’ or children’s health.
Author full text: https://authors.elsevier.com/a/1ctrxAOM9vmjQ
... For instance, oral reference doses (RfDs, mg kg À1 day À1 ), oral slope factor for carcinogenic risk (mg kg À1 day À1 ), drinking water unit risk (mg L À1 ), cancer risk level (CRL, mg L À1 ), minimal risk level (MRL, mg kg À1 day À1 ) are available for selected PBDE congeners such as BDE-47, -99, À153, À209, and other congeners of penta-BDE, octa-BDE, etc. (USEPA, 2017a). However, several other PBDEs and their products are widely used in the investigations, for which the above parameters are yet to be considered in case of BDE-15, -17, À28, À37, -52, À66, À92, À100, À 101, À102, À103, À133, À144, À146, À150, À161, À171, À172, À175, À 177, À178, À180, À182, À188, À193, À199, etc. (Keum and Li, 2005;Pan et al., 2019;Zhu et al., 2019). On a precautionary basis, it is advisable to evaluate the HRAs for all 209 known PBDE congeners. ...
... On a precautionary basis, it is advisable to evaluate the HRAs for all 209 known PBDE congeners. Traditional methods like GC/MS should be replaced with advanced analytical methods in order to simultaneously analyze low-to highbrominated PBDE congeners in a single run using GC coupled with an electron capture detector (GC-ECD) which is a cost-effective and time-saving approach (Oloruntoba et al., 2019). In addition, environmentally friendly parameters such as low hazardous, low migration, low bioavailability, good biodegradability, less interference between the debrominated products in the gaseous environment, etc. of PBDE congeners can be assessed by using an innovative approach called Derivatization-enhanced Raman spectroscopy (with Pharmacophore model) . ...
Polybrominated diphenyl ethers (PBDEs) serve as flame retardants in many household materials such as electrical and electronic devices, furniture, textiles, plastics, and baby products. Though the use of PBDEs like penta-, octa- and deca-BDE greatly reduces the fire damage, indoor pollution by these toxic emissions is ever-growing. In fact, a boom in the global market projections of PBDEs threatens human health security. Therefore, efforts are made to minimize PBDEs pollution in USA and Europe by encouraging voluntary phasing out of the production or imposing compelled regulations through Stockholm Convention, but >500 kilotons of PBDEs still exist globally. Both ‘environmental persistence’ and ‘bioaccumulation tendencies’ are the hallmarks of PBDE toxicities; however, both these issues concerning household emissions of PBDEs have been least addressed theoretically or practically. Critical physiological functions, lipophilicity and toxicity, trophic transfer and tissue specificities are of utmost importance in the benefit/risk assessments of PBDEs. Since indoor debromination of deca-BDE often yields many products, a better understanding on their sorption propensity, environmental fate and human toxicities is critical in taking rigorous measures on the ever-growing global deca-BDE market. The data available in the literature on human toxicities of PBDEs have been validated following meta-analysis. In this direction, the intent of the present review was to provide a critical evaluation of the key aspects like compositional patterns/isomer ratios of PBDEs implicated in bioaccumulation, indoor PBDE emissions versus human exposure, secured technologies to deal with the toxic emissions, and human toxicity of PBDEs in relation to the number of bromine atoms. Finally, an emphasis has been made on the knowledge gaps and future research directions related to endurable flame retardants which could fit well into the benefit/risk strategy.
... MSW are not separated at source in Nigeria. Consequently considerable quantities of plastics end up at the dumpsites where it becomes fuel of landfill/dumpsite fires with associated releases and exposure [58][59][60]. Other plastic products have currently a similar end of life fate including the plastics and polymer foams from products such as waste from EEE (WEEE) and EoL vehicles [26,53,61]. ...
... Since there is no effective solid waste sorting systems; mixed wastes including plastics end up in dumpsites where they are set on fire. These open burning methods result in the release of hazardous substances into the environment as a result of the plasticizers and flame retardants used in the plastics and contaminate air and soils and food [58,60,65,66]. ...
Background
Currently, plastic is at the top of the international agenda for waste management. Recent meetings of the Conferences of the Parties to the Basel and the Stockholm Conventions have expressed concerns over the impact of plastic waste, marine plastic litter, and microplastics, and emphasised the importance of reducing consumption and ensuring the environmentally sound management of waste plastics. This study presents the first continental historical analysis of mass importation and consumption of different polymers and plastics (primary and secondary forms, respectively) in Africa and the associated pollution potential. We identified, collated and synthesised dispersed international trade data on the importation of polymers and plastics into several African countries.
Results
The 33 African countries (total population of 856,671,366) with available data for more than 10 years imported approximately 86.14 Mt of polymers in primary form and 31.5 Mt of plastic products between 1990 and 2017. Extrapolating to the continental level (African population of 1.216 billion in 54 countries), about 172 Mt of polymers and plastics valued at $285 billion were imported between 1990 and 2017. Considering also the components of products, an estimated 230 Mt of plastics entered Africa during that time period, with the largest share going to Egypt (43 Mt, 18.7%), Nigeria (39 Mt, 17.0%), South Africa (27 Mt, 11.7%), Algeria (26 Mt, 11.3%), Morocco (22 Mt, 9.6%), and Tunisia (16 Mt, 7.0%). Additionally, primary plastic production in 8 African countries contributed 15 Mt during 2009–2015. The assessment showed that environmentally sound end-of-life management of waste plastics by recycling and energy recovery is in its infancy in Africa, but recycling activities and thermal recovery have started in a few countries.
Conclusions
Globally, the perception is that production and consumption of plastics can only increase in the future. Solutions are needed to tackle this global challenge. Certain policies and plastic bag bans could help reduce plastic consumption in the near future, as demonstrated by Rwanda. Furthermore, there is a need for innovative solutions such as the introduction of biodegradable polymers and other alternatives, especially for packaging.
... RQ rounded to significant digits. municipal dumpsite in Nabuja city, Nigeria, mean Σ 7 PBDEs ranged from 0.026 to 0.029 μg/g ww but the study did not include BDE 209 (Oloruntoba et al., 2019). Therefore, considering the concentrations detected and that hen eggs constitute a nutritious and essential diet, special attention should be given to control the concentration of contaminants in areas affected by e-waste residues. ...
Electrical and Electronic Equipment (EEE) residues and their management have been widely identified as potential sources of plasticizers and flame retardants to the environment, especially in non-formal e-waste facilities. This study evaluates the distribution, partitioning and environmental and human impact of organophosphate esters (OPEs), legacy polychlorinated biphenyls (PCBs), polybromodiphenyl ethers (PBDEs) and organochlorine pesticides (OCPs) in the e-waste recycling area of Baihe Tang village, in the Qingyuan county, Guangdong province, China. A plastic debris lump accumulated in a small pond during years was identified as the main source of pollution with ∑pollutants of 8400 μg/g dw, being OPEs the main contaminants detected, followed by PBDEs. This lump produced the contamination of water, sediments, soils and hen eggs in the surrounding area at high concentrations. Plastic-water and water-sediment partitioning coefficients explained the migration of OPEs to the water body and accumulation in sediments, with a strong dependence according to the KOW. Triphenyl phosphate (TPhP), tricresyl phosphate (TCPs) and high chlorination degree PCBs produced a risk in soils and sediments, considering the lowest predicted no effect concentration, while the presence of PCBs and PBDEs in free range hen eggs exceeded the acceptable daily intake. OCPs were detected at low concentrations in all samples. The presence of organic contaminants in e-waste facilities worldwide is discussed to highlight the need for a strict control of EEE management to minimize environmental and human risks.
... Hitherto, efforts have been made to characterize POPs chemicals, including CPs, in several matrices such as atmosphere, river, sediments, soil, indoor dust, biota, consumer products, human diet, blood and serum in Africa [26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41] . However, in the African continent, studies on PCNs in environmental matrices are yet to be investigated, hence the limited available information [3,10,42,43] . ...
Polychlorinated naphthalenes (PCNs) were listed as Persistent organic pollutants in the Stockholm Convention, in May 2015, because of their adverse health and environmental effects. PCNs production began in the early 1900s when they were used extensively in several consumer goods as fire retardants. However, because of their health and environmental implications, the production and use of PCNs chemicals were voluntarily banned in many countries in the 1970s and 1980s. However, PCNs are still detected in different environmental samples including air, water, sediments, soil, indoor dust, biota, consumer products, human diet, blood and serum today, as a result of their historical use and unintentional production. Thus, PCNs can be released into the environment throughout their life cycle. It becomes, therefore, crucial to monitor them in different environmental compartments. To date, about 163 reports on PCNs levels in several matrices have been published in different parts of the world. It was reported that toxic PCNs such as chloronaphthalenes 66, 67 and 73 are prevalent in most samples; thus, there is a need to continuously monitor these congeners in our environment. However, there are sparse studies related to PCNs levels, not only in consumer products, leachates and sediment samples from landfill sites in Africa but also in other matrices, leaving a huge research gap that must be prioritized. To date, only about 3 studies on PCNs have been published in Africa, bearing in mind that there is no documented evidence of any known production of PCNs in the continent. Thus, a wide research gap in PCNs studies still exists in Africa. There is an urgent need, therefore, to conduct studies and establish robust PCNs inventories in Africa. The present review examines the existing knowledge on PCNs levels and trends in Africa, and identifies research gaps that ought to be addressed so that the scale of PCNs distribution in the global environment can be known.
... The global trade in plastic waste has seen a movement of significant volumes from developed to developing countries, where environmentally unsound recycling and disposal practices are leading to exposures to toxic constituents [65e67]. Examples include landfill or dump site fires with associated releases of toxic plastic compounds [11, [68][69][70][71] as well as plastic additives released in leachates from landfills and detected in the surrounding areas [72,73]. While for few investigated plastic additives, releases from landfills and exposures are documented, such assessments are missing for the wider range of plastic-related substances. ...
Enabling a circular economy for plastics in Europe and beyond is an ambitious goal. In order to reach a fully closed loop, numerous challenges and knowledge gaps need to be overcome. This review provides a list of more than 6000 chemicals reported to be found in plastics and an overview of the challenges and gaps in assessing their impacts on the environment and human health along the life cycle of plastic products. We further identified 1518 plastic-related chemicals of concern, which should be prioritized for substitution by safer alternatives. At last, we propose five policy recommendations, including the need of a global and overarching regulatory framework for plastics and related chemicals, in support of a circular economy for plastics and of target 12.4 of the UN Sustainable Development Goals (SDGs).
... and 3% nonabromodiphenyl ethers have the largest application in the market due to their low price and superior performance (Luo et al. 2007;Sun et al. 2020), accounting for more than 75% of the total ame retardants (Sakai et al. 2001). BDE-209 is usually used in circuit boards, textiles and other products as additive ame retardants (Talsness.2008;Oloruntoba et al. 2019). ...
Low brominated diphenyl ethers and brominated dioxins with high toxicity were easily produced in the pyrolysis process of decabromodiphenyl ethers, Based on this, the pyrolysis process of BDE-209 and ZnO was studied by differential thermal gravimetric analysis (DTA-TG), X-ray diffraction (XRD), GC and GC / MS. The results showed that the addition of zinc oxide reduced the activation energy of BDE-209 thermal degradation reaction, thus reducing the thermal degradation temperature of BDE-209; after the addition of zinc oxide, BDE-209 pyrolysis produced more brominated dioxins at 400 ℃ When BDE-209 and ZnO were degraded at 400 ℃ at 2.4:1 (w / W), the degradation rate reached 100% at 2 h. At this time, the relative content of hexabromo- and heptabromo- dioxins was lower, and the relative content of hexabromobenzene and pentabromobenzene was the highest. Combined with Arrhenius formula calculation, soft and hard acid-base theory and XRD product analysis of pyrolysis residue, the mixed pyrolysis mechanism of BDE-209 and zinc oxide was deeply discussed, which provided a theoretical basis for pollution prevention and control of waste printed circuit boards in heat treatment.
... Their occurrence in deep oceans consequently shows that they are widespread and ubiquitous environmental contaminants [61][62][63]. PBDEs have been detected at significant concentrations in environmental matrices like air [64], suspended particulate matter [41,65], hair [66] soil [67,68], surface water [69], sediment [70,71] and sewage sludge [72,73] and also biological samples like biota [74,75], food stuff [76], human blood [77,78], and plasma [79,80], indoor dust [81,82], placenta [83,84], adipose tissues [85,86], liver [87], fish [71,88], mussels [88], bird [89], human amniotic fluid [90], human serum [91,92], urine [93], semen [78,94] and breast milk [95,96]. ...
PBDEs are human-influenced chemicals utilized massively as flame retardants. They are environmentally persistent, not easily degraded, bioaccumulate in the biological tissue of organisms, and bio-magnify across the food web. They can travel over a long distance, with air and water being their possible transport media. They can be transferred to non-target organisms by inhalation, oral ingestion, breastfeeding, or dermal contact. These pollutants adsorb easily to solid matrices due to their lipophilicity and hydrophobicity; thus, sediments from rivers, lakes, estuaries, and ocean are becoming their major reservoirs aquatic environments. They have low acute toxicity, but the effects of interfering with the thyroid hormone metabolism in the endocrine system are long term. Many congeners of PBDEs are considered to pose a danger to humans and the aquatic environment. They have shown the possibility of causing many undesirable effects, together with neurologic, immunological, and reproductive disruptions and possible carcinogenicity in humans. PBDEs have been detected in small amounts in biological samples, including hair, human semen, blood, urine, and breastmilk, and environmental samples such as sediment, soil, sewage sludge, air, biota, fish, mussels, surface water, and wastewater. The congeners prevailing in environmental samples, with soil being the essential matrix, are BDE 47, 99, and 100. BDE 28, 47, 99, 100, 153, 154, and 183 are more frequently detected in human tissues, whereas in sediment and soil, BDE 100 and 183 predominate. Generally, BDE 153 and 154 appear very often across different matrices. However, BDE 209 seems not frequently determined, owing to its tendency to quickly breakdown into smaller congeners. This paper carried out an overview of PBDEs in the environmental, human, and biota niches with their characteristics, physicochemical properties, and fate in the environment, human exposure, and health effects.
... As mentioned above, waste containing PBDEs are largely disposed to landfills in Kuwait. From other country experience PBDEs (and other POPs) are released to some extent from landfills and dump sites [55] with potential exposure to cattle and chicken in the surrounding [56]. Therefore soils around landfills were sampled (Fig. 1) and analyzed for PBDEs. ...
Since 2006, Kuwait has been a party to the Stockholm Convention (SC) on Persistent Organic Pollutants (POPs). According to Article 7 of the SC, each party should develop a National Implementation Plan (NIP) and endeavor to implement the plan for the control and elimination of POPs. A first detailed National Implementation Plan has been developed for Kuwait with the support of the Stockholm Convention Regional Center for Capacity-Building and the Transfer of Technology for West Asia (SCRC Kuwait) in KISR. It includes a detailed action plan to manage and control the POPs in the country but also with activities to further give regional support for POPs monitoring and management. The current paper discusses the major inventory findings for the individual POPs groups including POPs pesticides, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers, and hexabromocyclododecane (HBCD) as well as Perfluorooctanesulfonic acid (PFOS) and unintentional POPs. Besides, information from POPs monitoring studies in Kuwait relevant to the NIP is shortly compiled for further informing on the current situation of POPs in Kuwait. Selected soil samples were collected and analyzed for selected POPs during the NIP development to generate supplementary information to the POP monitoring studies already conducted in Kuwait. Further relevant areas for the POPs management and control were assessed during the NIP development and are listed in the paper. One finding in the NIP assessment was that some of the alternatives used are also bioaccumulative with toxicity in biota and that in the NIP implementation. Also, alternative pesticides in the current use are an issue of concern. Therefore one activity in the
implementation of the NIP is the avoidance of regrettable alternatives and the use of more sustainable and green chemicals.
The European Commission asked EFSA to update its 2011 risk assessment on polybrominated diphenyl ethers (PBDEs) in food, focusing on 10 congeners: BDE‐28, ‐47, ‐49, ‐99, ‐100, ‐138, ‐153, ‐154, ‐183 and ‑209. The CONTAM Panel concluded that the neurodevelopmental effects on behaviour and reproductive/developmental effects are the critical effects in rodent studies. For four congeners (BDE‐47, ‐99, ‐153, ‐209) the Panel derived Reference Points, i.e. benchmark doses and corresponding lower 95% confidence limits (BMDLs), for endpoint‐specific benchmark responses. Since repeated exposure to PBDEs results in accumulation of these chemicals in the body, the Panel estimated the body burden at the BMDL in rodents, and the chronic intake that would lead to the same body burden in humans. For the remaining six congeners no studies were available to identify Reference Points. The Panel concluded that there is scientific basis for inclusion of all 10 congeners in a common assessment group and performed a combined risk assessment. The Panel concluded that the combined margin of exposure (MOET) approach was the most appropriate risk metric and applied a tiered approach to the risk characterisation. Over 84,000 analytical results for the 10 congeners in food were used to estimate the exposure across dietary surveys and age groups of the European population. The most important contributors to the chronic dietary Lower Bound exposure to PBDEs were meat and meat products and fish and seafood. Taking into account the uncertainties affecting the assessment, the Panel concluded that it is likely that current dietary exposure to PBDEs in the European population raises a health concern.
This study determines the levels of 49 persistent organic pollutants which were grouped into polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDDs), in infant formula and varieties of baby food. The analyzed samples (n = 80) came from stores all over Poland. The presence of PCDD/F, PCDD/F/PCB and non dioxin-like (ndl)-PCB congeners above the maximum levels stipulated in Commission Regulation (EU) No 1259/2011 was not detected in any sample. The determined average content of PCDD/Fs/dl-PCBs in the tested baby foods was in the range of 4-10 % of the maximum level, and content of ndl-PCBs was in the range of 2-6 % of the maximum level. Despite these low levels of dioxins, furans, and PCBs, a risk analysis assuming weekly consumption of the recommended food intake showed exceedances of the tolerable weekly intake (TWI). The content of flame retardants was low in all examined categories of food for children and infant formula. The lower-bound concentration of the sum of HBCDD isomers (LB ∑HBCDDs) ranged from below the limit of quantification (LOQ) to 0.0313 ng/g w.w. and the concentration of ∑PBDEs was in a 0.001-1.014 ng/g w.w. range. Neither infant formula nor baby food contributed considerably to infant exposure to HBCDDs or PBDEs. Our research indicates that the safe exposure thresholds for dioxins and PCBs in foods for infants and young children may be too high and perhaps it may be necessary to amend the legislation setting acceptable limits for baby food. It seems reasonable to introduce a recommendation on the frequency of food consumption for children and the control of raw materials for food production, in particular fish and cow milk, should be a permanent control point in the food safety assurance system.
A sensitive and reliable method for determining 25 polybrominated diphenyl ethers (PBDEs) in Chinese mitten crabs and their ecosystems ranging from the growing environment to edible feed by gas chromatography coupled to triple quadrupole mass spectrometry with advanced electron ionization (GC-AEI-MS/MS) was developed and validated. Accelerated solvent extraction (ASE) and liquid-liquid extraction were used to extract solid and water samples, respectively. On the basis of a traditional acid-base silica column, deactivated silica was added and n-hexane elution was used to increase the effect of separation and purification. Two oven temperature programs were applied to achieve good separation of low brominated congeners and increase the sensitivity of high brominated congeners. The method provided good linearity (>0.9996). The recoveries of four matrices were in the range of 82-115% and the method quantification limits (MQLs) in crabs, feed, sediment and water ranged from 0.36-6 pg per g wet weight, 0.69-22.29 pg per g dry weight, 1.02-25.26 pg per g dry weight, and 2.43-40.14 pg L-1, respectively. The proposed method was used for ten samples from two aquatic sites and PBDEs were detected in Chinese mitten crabs, commercial feed and sediment, with the highest in crabs. This analytical technique can be used to monitor the content and the accumulation behavior of PBDEs in Chinese mitten crab ecosystems or other aquaculture systems.
Here is reported effervescent reaction-enhanced switchable hydrophilic-hydrophobic solvent-based salting-out microextraction (ERSSM) with high-performance liquid chromatography with photodiode array detection (HPLC-PDA) for the preconcentration, extraction, and trace-level determination of polybrominated diphenyl ethers (PBDEs) in milk and water. The important variables were rigorously optimized to be 150 µL of hexanoic acid as the extraction solvent, 400 µL of Na2CO3 as the alkaline source, 350 µL of H2SO4 solution as the acid source, and NaCl as the salting-out agent. The optimized conditions provided a linear range from 0.2 to 50 µg L⁻¹ with limits of detection and quantitation from 0.026 to 0.085 µg L⁻¹ and 0.087 to 0.28 µg L⁻¹ for six PBDEs. The intra-day and inter-day precision values were from 2.48% to 6.75%, and the fortified recoveries for PBDEs were between 78.06% and 103.07% in water and milk samples. The developed procedure avoids the use of a traditional organic disperser and mechanical mixing allowing the determination of PBDEs outdoors by synchronous extraction method and high efficiency for the analytes. These advantages suggest a high potential for the routine monitoring of PBDEs in liquid food and environmental samples.
The microplastics (MPs) existed in the environment widely has resulted in novel thinking about in-situ remediation techniques, such as nano-zero-valent iron (nZVI) and sulfided nZVI (S-nZVI), which were often compromised by various environmental factors. In this study, three common MPs such as polyvinyl chloride (PVC), polystyrene (PS), and polypropylene (PP) in soil were found to inhibit the degradation rate of decabromodiphenyl ether (BDE209) by nZVI and S-nZVI to different degrees due to MPs inhibiting of electron transfer which is the main way to degrade BDE209. The inhibition strength was related to its impedance (Z) and electron-accepting (EAC)/-donating capacity (EDC). Based on the explanation of the inhibition mechanism, the reason for different aging degrees of nZVI and S-nZVI in different MPs was illustrated, especially in PVC systems. Furthermore, the aging of reacted MPs, functionalization and fragmentation in particular, indicated that they were involved in the degradation process. Moreover, this work provided new insights into the field application of nZVI-based materials for removing persistent organic pollutants (POPs).
Decabromodiphenyl ether (BDE-209), the primary constituent of a widely used flame retardant formulation, is often present in high levels in avian derived products and could be transferred to humans through consumption. The purpose of this study was to investigate the toxicokinetics and bioaccumulation patterns of BDE-209 in different tissues of broilers, which would benefit the evaluation of chicken product safety. Male broilers received a single oral administration of BDE-209 at 25 mg/kg.BW and then BDE-209 concentrations in the plasma, liver, leg muscle, breast muscle, and other tissues were measured using gas chromatography-electron capture detection (GC-ECD). The changes of BDE-209 concentrations in the plasma were fitted to a non-compartmental model for kinetic analysis. Peak values were observed at 24 h (t1/2 =168.28 h), and trace levels remained for four weeks. Additionally, Cmax in the liver was much higher than that in leg and breast muscles, and Tmax from the liver and muscle were 12 and 24 h, respectively. Residual BDE-209 was detected in all broiler tissues after 2 weeks, and concentrations were ranked as follows: fat > liver > thymus gland > heart > testis > thigh muscle > skin > lung > kidney > breast muscles > spleen (wet weight (ww)). Our results suggested that BDE-209 was widely distributed in different tissues after intestinal absorption, and preferentially accumulated in adipose and liver tissues. Observations of bioaccumulation and slow elimination in the liver and muscles provide critical insight into the toxicity of BDE-209 and risk assessment of edible tissues from broilers.
Certain chemicals/materials that are contaminants of emerging concern (CECs) have been widely detected in water bodies and terrestrial systems worldwide while other CECs occur at undetectable concentrations. The primary sources of CECs in farmlands are agricultural inputs, such as wastewater, biosolids, sewage sludge, and agricultural mulching films. The percent increase in cropland area during 1950-2016 was 30 and the rise in land use for food crops during 1960-2018 was 100-500%, implying that there could be a significant CEC burden in farmlands in the future. In fact, the alarming concentrations (μg kg-1) of certain CECs such as PBDEs, PAEs, and PFOS that occur in farmlands are 383, 35 400 and 483, respectively. Also, metal nanoparticles are reported even at the mg kg-1 level. Chronic root accumulation followed by translocation of CECs into plants results in their detectable concentrations in the final plant produce. Thus, there is a continuous flow of CECs from farmlands to agricultural produce, causing a serious threat to the terrestrial food chain. Consequently, CECs find their way to the human body directly through CEC-laden plant produce or indirectly via the meat of grazing animals. Thus, human health could be at the most critical risk since several CECs have been shown to cause cancers, disruption of endocrine and cognitive systems, maternal-foetal transfer, neurotoxicity, and genotoxicity. Overall, this comprehensive review provides updated information on contamination of chemicals/materials of concern in farmlands globally, sources for their entry, uptake by crop plants, and their likely impact on the terrestrial food chain and human health.
Open burning is a waste management practice performed by many people worldwide, especially in developing countries. Lack of detailed data of open burning practices may lead to a misinterpretation during data analysis, especially when estimating global/local emissions and assessing risks. This study presents a comprehensive review of current research trends, methodological assessments, and factors behind open waste burning practices from published literature. This review used systematic methods such as PRISMA 2020 methodology, a bibliometric approach, and qualitative content analysis to determine and assess 84 articles related to open burning. The results show that environmental risks and emission factors related to open burning incidents at the landfill or residential level are preferable topics that will be rising in the years to come. Coupling methods such as a transect-based approach with a questionnaire survey and mobile-static plume sampling to determine the activities and incidents as baseline data for risk assessment will help researchers gain a robust dataset of open burning emission inventory. In addition, it was found that environmental knowledge and awareness levels influence open burning practices, thereby opening up opportunities for future research.
Supplementary information:
The online version contains supplementary material available at 10.1007/s10163-022-01430-9.
Polybrominated diphenyl ethers (PBDEs) were listed in the Stockholm Convention as POPs because of their bio-accumulative, long-range and toxicity characteristics. Therefore, these should be managed and assessed by Parties of the convention in an environmentally sound manner. This present study assessed the status of PBDEs contamination at e-waste dumpsites in Lagos, Nigeria. Soil and sediment samples were collected from 3 e-waste dumpsites and water samples were collected from rain water ponds located within the e-waste dumpsites vicinities and control sites over a period of two years. The concentrations of ∑7PBDEs in soils from the e-waste dumpsites at 0–15 cm depth for the first and second year ranged from 141 to 302 ngg⁻¹ dry weight, respectively while that of the control soils was 13.2–27.2ngg⁻¹ dry weight. These high concentrations may be attributed to the fact that open burning of electronic waste was the regular method of reducing the volume of e-waste at the sites. PBDE levels across the soil profile from 0 to 45 cm depth showed a gradual increase in PBDEs accumulation in the topsoil and migration into the sub-soil over the period of 2 years, but with no significant difference (p-value = 0.89). Sediments and water from the rain water ponds around the dumpsites were found to be contaminated by PBDEs with levels ranging from 51.4 to 85.8ngg⁻¹ and 14.4 to 27.4ngg⁻¹, respectively, while levels in control for sediment and water are 11.5ngg⁻¹ and 2.43ngg⁻¹respectively.These, however indicates that there was significance difference between the PBDEs levels in water and sediment from the study sites with those of their respective controls (p-value for water was 0.01, while that for sediment was 0.03).The levels of PBDEs in this study sites were higher than those of the respective control. The range of PBDEs in e-waste dumpsites was comparable to those reported in USA and Europe but lower than those from China. Environmental samples from the e-waste dumpsites in Lagos were contaminated with PBDEs, there is therefore the need for proper disposal methods for end-of-life products especially those containing PBDEs in Nigeria.
The contamination of 2,2’,4,4’-Tetrabrmodiphenyl ether (BDE-47) and perfluorooctanoic acid (PFOA) has drawn a worldwide attention over the risks in ecological and food safety. In this work, blue mussel (Mytilus galloprpvincialis) was employed to investigate the combined effects of BDE-47 (10 ng mL⁻¹) and PFOA (100 ng mL⁻¹) on tissue distribution, accumulation, elimination, and toxicity. Results suggested that BDE-47 and PFOA accumulated mostly in digestive gland, followed by gills and gonad, and M. galloprovincialis displayed higher accumulation capacity to BDE-47 than PFOA. Co-exposure treatment reduced the accumulation of BDE-47, and enhanced the accumulation of PFOA. Furthermore, biochemical and histopathological tests revealed that the aggravated toxicity in co-exposure groups was mainly attributed to the oxidative stress and damage of tissue structure. This work could be helpful to get a better understanding of the combined behaviors and cumulative risks of BDE-47 and PFOA in marine ecosystem.
Tetrabromodiphenyl ether (BDE-47) is widely used as commercial flame retardants that can be released into the environment and finally enter human body through the food chain. It has been identified to generate neurotoxicity, but little is known about auditory damage and the underlying mechanism following BDE-47 exposure. This study aimed to assess the cell viability with BDE-47 concentration ranging from 0 to 150 μM in mouse organ of Corti-derived cell lines (HEI-OC1). Aryl hydrocarbon receptor (AhR) as an environmental sensor, reactive oxygen species (ROS), NLRP3 inflammasome and p38 MAPK pathways were detected. Results: (1) BDE-47 inhibited the viability in a time- and dose-dependent way in HEI-OC1 cells. Cell cycle was arrested in G1 phase by BDE-47; (2) Elevated intracellular ROS, LDH levels and necrosis were found, which was alleviated by pretreatment with ROS scavenger N-acetylcysteine (NAC); (3) AhR plays an essential role in ligand-regulated transcription factor activation by exogenous environmental compounds. We found increased expression of AhR and decreased downstream targets of CYP 1A1 and CYP 1B1 in BDE-47-treated HEI-OC1 cells, which was reversed by the AhR antagonist CH-223191 for 2 h before BDE-47 exposure. No significant change was detected in CYP 2B; (4) Enhanced expressions of NLRP3 and caspase-1 were induced by BDE-47, with up-regulations of both pro-inflammatory factors for IL-1β, IL-6 and TNF-α, and anti-inflammatory factors for IL-4, IL-10 and IL-13, but down-regulation for IL-1α; (5) Additionally, the p38 MAPK signaling pathway was activated with increased phosphorylation levels of MKK/3/6, p38 MAPK and NF-kB. Overall, our findings illustrate a role of AhR in ROS-induced necrosis of cochlear hair cells by BDE-47 exposure, in which NLRP3 inflammasome and p38 MAPK signaling pathways are activated. The current study first elucidates the sense of hearing damage induced by BDE-47, and cell-specific or mixture exposures in vivo or human studies are needed to confirm this association.
Emerging pollutants represent a group of synthetic or naturally occurring compounds that are not normally monitored within the environment but can enter into the environment and cause different adverse ecological and health effects. This systematic review identified the various emerging pollutants in Nigeria. The following databases, ScienceDirect, PubMed, Google Scholar, and African Journals OnLine (AJOL) were searched to identify studies on pollutants of emerging concerns in Nigeria. A total of 933 articles were identified out of which 30 articles were selected to be eligible for the study. Over 250 emerging pollutants were identified and divided into 9 major groups which are personal care products, pharmaceuticals, industrial chemicals, polycyclic aromatic hydrocarbons, volatile organic compounds, pesticides, mycotoxins, radionuclides and electromagnetic radiations (Gamma radiation) and other pollutants of emerging concerns such as microbes, microplastics, and particulate matter. These pollutants are found in water bodies and underground waters, soils and sediments, biological
systems, and ambient air at different concentrations with seasonal variations. Some of these pollutants act as endocrine disruptors, β-adrenergic receptors agonist blockers, oxidative stress inducers and can cause genetic alterations in DNA and epigenetic reprogramming through global DNA methylation, gene-specific CpG methylation and microRNA expression. Emerging pollutants of public health concern in Nigeria are on the increase and are threat to both ecological and human health.
This report gives a summary of the historic use, former management and current release of polychlorinated biphenyls (PCBs) in Germany and assesses the impact of the life cycle of PCBs on the contamination of the environment and of food products of animal origin. In Germany 60,000 t of PCBs were used in transformers, capacitors or as hydraulic oils. The use of PCB oils in these “closed applications”, has been banned in Germany in 2000. Thirty to 50% of these PCBs were not appropriately managed. In West Germany, 24,000 t of PCBs were used in open applications, mainly as additive (plasticiser, flame retardant) in sealants and paints in buildings and other construction. The continued use in open applications has not been banned, and in 2013, an estimated more than 12,000 t of PCBs were still present in buildings and other constructions. These open PCB applications continuously emit PCBs into the environment with an estimated release of 7–12 t per year. This amount is in agreement with deposition measurements (estimated to 18 t) and emission estimates for Switzerland. The atmospheric PCB releases still have an relevant impact on vegetation and livestock feed. In addition, PCBs in open applications on farms are still a sources of contamination for farmed animals. Furthermore, the historic production, use, recycling and disposal of PCBs have contaminated soils along the lifecycle. This legacy of contaminated soils and contaminated feed, individually or collectively, can lead to exceedance of maximum levels in food products from animals. In beef and chicken, soil levels of 5 ng PCB-TEQ/kg and for chicken with high soil exposure even 2 ng PCB-TEQ/kg can lead to exceedance of EU limits in meat and eggs. Areas at and around industries having produced or used or managed PCBs, or facilities and areas where PCBs were disposed need to be assessed in respect to potential contamination of food-producing animals. For a large share of impacted land, management measures applicable on farm level might be sufficient to continue with food production. Open PCB applications need to be inventoried and better managed. Other persistent and toxic chemicals used as alternatives to PCBs, e.g. short chain chlorinated paraffins (SCCPs), should be assessed in the life cycle for exposure of food-producing animals and humans.
Background:
Endocrine-disrupting chemicals (EDCs) contribute to disease and dysfunction and incur high associated costs (>1% of the gross domestic product [GDP] in the European Union). Exposure to EDCs varies widely between the USA and Europe because of differences in regulations and, therefore, we aimed to quantify disease burdens and related economic costs to allow comparison.
Methods:
We used existing models for assessing epidemiological and toxicological studies to reach consensus on probabilities of causation for 15 exposure-response relations between substances and disorders. We used Monte Carlo methods to produce realistic probability ranges for costs across the exposure-response relation, taking into account uncertainties. Estimates were made based on population and costs in the USA in 2010. Costs for the European Union were converted to US$ (€1=$1·33).
Findings:
The disease costs of EDCs were much higher in the USA than in Europe ($340 billion [2·33% of GDP] vs $217 billion [1·28%]). The difference was driven mainly by intelligence quotient (IQ) points loss and intellectual disability due to polybrominated diphenyl ethers (11 million IQ points lost and 43 000 cases costing $266 billion in the USA vs 873 000 IQ points lost and 3290 cases costing $12·6 billion in the European Union). Accounting for probability of causation, in the European Union, organophosphate pesticides were the largest contributor to costs associated with EDC exposure ($121 billion), whereas in the USA costs due to pesticides were much lower ($42 billion).
Interpretation:
EDC exposure in the USA contributes to disease and dysfunction, with annual costs taking up more than 2% of the GDP. Differences from the European Union suggest the need for improved screening for chemical disruption to endocrine systems and proactive prevention.
Funding:
Endocrine Society, Ralph S French Charitable Foundation, and Broad Reach Foundation.
Recently, certain polybrominated diphenyl ethers (PBDEs) have been listed as persistent organic pollutants (POPs) in the Stockholm Convention. In this study, a preliminary material and substance flow analysis of commercial pentabromodiphenyl ether (c-PentaBDE) was conducted for motor vehicles—a major use sector for POP-PBDE in polyurethane (PUR) foam—for Nigeria. The methodology of the Stockholm Convention PBDE inventory guidance was used for the calculation of c-PentaBDE. Material/substance flow analysis was conducted applying the STAN software. The time frame for this analysis was 1980–2010, considering that this was the period when POP-PBDE-containing vehicles were largely imported into Nigeria.
It is estimated that the approximately 19 million passenger cars imported from 1980 to 2010 contained ca. 270 t of POP-PBDEs in ca. 401,000 t of PUR foam. A major share of cars from the USA and only a small share of cars from Europe and Asia were impacted. This simplified material and substance flow of PUR foams and POP-PBDEs in motor vehicles demonstrated the potential for environmental/human contamination and pollution of recycling/reuse for Nigeria and other developing countries.
The study developed the first preliminary inventory of end-of-life vehicles for Nigeria, following which the environment ministry has taken up the important issue of end-of-life vehicles management. Considering that a range of other pollutants are contained in vehicles (e.g. heavy metals, flame retardants, PCBs, chlorofluorocarbons, hydrofluorocarbons and waste oil), this initiated activity should finally lead to an integrated management of pollutants and resources from the transport sector.
A previous report documented that endocrine disrupting chemicals contribute substantially to certain forms of disease and disability. In the present analysis, our main objective was to update a range of health and economic costs that can be reasonably attributed to endocrine disrupting chemical exposures in the European Union, leveraging new burden and disease cost estimates of female reproductive conditions from accompanying report. Expert panels evaluated the epidemiologic evidence, using adapted criteria from the WHO Grading of Recommendations Assessment, Development and Evaluation Working Group, and evaluated laboratory and animal evidence of endocrine disruption using definitions recently promulgated by the Danish Environmental Protection Agency. The Delphi method was used to make decisions on the strength of the data. Expert panels consensus was achieved for probable (>20%) endocrine disrupting chemical causation for IQ loss and associated intellectual disability; autism; attention deficit hyperactivity disorder; endometriosis; fibroids; childhood obesity; adult obesity; adult diabetes; cryptorchidism; male infertility, and mortality associated with reduced testosterone. Accounting for probability of causation, and using the midpoint of each range for probability of causation, Monte Carlo simulations produced a median annual cost of €163 billion (1.28% of EU Gross Domestic Product) across 1000 simulations. We conclude that endocrine disrupting chemical exposures in the EU are likely to contribute substantially to disease and dysfunction across the life course with costs in the hundreds of billions of Euros per year. These estimates represent only those endocrine disrupting chemicals with the highest probability of causation; a broader analysis would have produced greater estimates of burden of disease and costs.
Polybrominated diphenyl ethers (PBDEs) were the first brominated persistent organic pollutants (POPs) listed in the Stockholm Convention. Parties to the convention are currently establishing inventories for developing action plans for the environmentally sound management of PBDE-containing materials. The major use of commercial octabromodiphenyl ether (c-OctaBDE) has been in casings from cathode ray tube (CRT) TVs and computer monitors. Large quantities of used e-waste and electronic equipment have been exported to developing countries with Nigeria being a major importer in Africa. The casings from 382 TVs and computers imported from major world regions to Nigeria were sampled in backyards and waste dumps. The samples were screened with X-ray flourescence (XRF) for bromine and analysed by gas chromatography/ electron capture detection (GC/ECD) for brominated flame retardants (BFRs). A high proportion of the CRT casings (61 %) contained more than 10,000 ppm bromine from BFRs. Decabromodiphenyl ether (DecaBDE) was the major flame retardant used in TV sets and tetrabromobisphenol A (TBBPA) for computer CRTs.
The screening suggests that average PBDE levels (of c-OctaBDE + DecaBDE) in Nigerian-stockpiled CRT casings were 1.1 % for TV and 0.13 % for PC CRTs. These are above the Restriction of Hazardous Substances (RoHS) limit and should be separated for RoHS compliant recycling. The Nigerian e-waste inventory of 237,000 t of CRT plastic would therefore contain approx. 594 t c-OctaBDE and 1,880 t of DecaBDE. In Nigeria, as for most developing countries, there is currently no adequate e-waste management, plastic separation or destruction capacity. The data highlight the urgent need to develop environmentally sound management for this large material flow.
A simple analytical procedure was developed for simultaneous determination of trace levels of tri- to hepta-BDEs as well as 2,2′,4,4′,5,5′-hexabromobiphenyl (BB 153). The mechanical shaking extraction technique for the isolation of target analytes was optimised. Different extraction solvent combinations were tested under different extraction time periods of 3, 6, 12 and 16 h. The n-hexane:acetone (2:1, v/v) combination gave the best recovery at the optimum extraction of 12 h. Target analytes were quantified using a high capillary gas chromatograph (GC) equipped with an electron capture detector. Under the optimum GC conditions, the resolution of the co-eluting BDE 154 and BB 153 was achieved. The overall recoveries of target analytes in the matrix spike experiment conducted ranged between 84.4 and 110% for BDE 183 and BDE 28, respectively. The method was applied to 19 field sediment samples collected from a control site and from 3 sampling locations (upstream, point of discharge and downstream) of the Black River, which receives effluent from a wastewater treatment plant (WWTP). The sum of the mean concentrations of all of the 7 PBDE congeners was 4.63, 0.35, 'not detectable' and 4.43 ng/g, for the control site, upstream, point of discharge and downstream samples, respectively. The concentrations of BB 153 were generally low in these samples and ranged between ND and 0.89 ng/g. The developed method allows for the simultaneous determination of PBDE congeners and BB 153. It is efficient, moderately rapid and cost-effective.
Chicken eggs categorised as conventional, omega-3 enriched, free range and organic were collected at grading stations in three regions of Canada between 2005 and 2006. Free run eggs, which were only available for collection from two regions, were also sampled during this time frame. Egg yolks from each of these egg types (n = 162) were analysed to determine brominated flame retardant levels, specifically polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD). PBDEs were detected in 100% of the 162 samples tested, while HBCD was observed in 85% of the egg yolks. Total PBDE concentrations in egg yolks ranged from 0.018 to 20.9 ng g(-1) lipid (median = 3.03 ng g(-1) lipid), with PBDE 209 identified as being the major contributor to ΣPBDE concentrations. In addition to PBDE 209, PBDE 99, 47, 100, 183 and 153 were important contributors to ΣPBDE concentrations. Total HBCD concentrations ranged from below the limit of detection to a maximum concentration of 71.9 ng g(-1) lipid (median = 0.053 ng g(-1) lipid). The α-isomer was the dominant contributor to ΣHBCD levels in Canadian egg yolks and was the most frequently detected HBCD isomer. ΣPBDE levels exhibited large differences in variability between combinations of region and type. ΣHBCD concentrations were not significantly different among regions, although differences were observed between the different types of egg yolks analysed in the present study.
Since the 1970s, an increasing number of regulations have expanded the use of brominated and chlorinated flame retardants. Many of these chemicals are now recognized as global contaminants and are associated with adverse health effects in animals and humans, including endocrine and thyroid disruption, immunotoxicity, reproductive toxicity, cancer, and adverse effects on fetal and child development and neurologic function. Some flame retardants such as polybrominated diphenyl ethers (PBDEs) have been banned or voluntarily phased out by manufacturers because of their environmental persistence and toxicity, only to be replaced by other organohalogens of unknown toxicity. Despite restrictions on further production in some countries, consumer products previously treated with banned retardants are still in use and continue to release toxic chemicals into the environment, and the worldwide use of organohalogen retardants continues to increase. This paper examines major uses and known toxic effects of commonly-used organohalogen flame retardants, replacements for those that have been phased out, their combustion by-products, and their effectiveness at reducing fire hazard. Policy and other solutions to maintain fire safety while reducing toxicity are suggested. The major conclusions are: (1) Flammability regulations can cause greater adverse environmental and health impacts than fire safety benefits. (2) The current options for end-of-life disposal of products treated with organohalogens retardants are problematic. (3) Life-cycle analyses evaluating benefits and risks should consider the health and environmental effects of the chemicals, as well as their fire safety impacts. (4) Most fire deaths and most fire injuries result from inhaling carbon monoxide, irritant gases, and soot. The incorporation of organohalogens can increase the yield of these toxic by-products during combustion. (5) Fire-safe cigarettes, fire-safe candles, child-resistant lighters, sprinklers, and smoke detectors can prevent fires without the potential adverse effects of flame retardant chemicals. (6) Alternatives to organohalogen flame retardant chemicals include using less flammable materials, design changes, and safer chemicals. To date, before evaluating their health and environmental impacts, many flame retardant chemicals have been produced and used, resulting in high levels of human exposure. As a growing literature continues to find adverse impacts from such chemicals, a more systematic approach to their regulation is needed. Before implementing new flammability standards, decision-makers should evaluate the potential fire safety benefit versus the health and environmental impacts of the chemicals, materials, or technologies likely to be used to meet the standard. Reducing the use of toxic or untested flame retardant chemicals in consumer products can protect human and animal health and the global environment without compromising fire safety.
This study was designed to update previous U.S. market basket surveys of levels and polybrominated diphenyl ether (PBDE) dietary intake calculations. This study also quantifies hexabromocyclododecane (HBCD) levels in U.S.-purchased foods for the first time and estimates U.S. dietary intake of HBCD. This is part of a larger market basket study reported in two companion articles, of current levels of certain persistent organic pollutants (POPs) PBDEs, HBCD, perfluorinated compounds, polychlorinated biphenyls, and pesticides in composite food samples collected in 2008-2009.
In this study, we measured concentrations of 24 PBDE congeners and total HBCD in composite samples of 31 food types (310 samples). U.S. dietary intake of PBDEs and HBCD was estimated referencing the most current U.S. Department of Agriculture loss-adjusted food availability report.
Total PBDE concentrations in food varied by food type, ranging from 12 pg/g wet weight (ww) in whole milk to 1,545 pg/g ww in canned sardines and 6,211 pg/g ww in butter. Total HBCD concentrations also varied substantially within and among food groups, ranging from 23 pg/g in canned beef chili to 593 pg/g in canned sardines. HBCD was not detected in any dairy samples. Dietary intake of all PBDE congeners measured was estimated to be 50 ng/day, mostly from dairy consumption but also from meat and fish. HBCD intake was estimated at 16 ng/day, primarily from meat consumption.
PBDEs and HBCDs currently contaminate some food purchased in the United States, although PBDE intake estimated in this study is lower than reported in our previous market basket surveys. HBCD is in food at higher levels than expected based on previously reported levels in milk and blood compared with PBDE levels and is comparable to European levels.
Human exposure to polybrominated diphenyl ethers (PBDEs) is virtually universal in the United States. Although the uses of these chemicals as flame retardants in fabrics, foams, and plastics are well defined, human exposure pathways are not well understood.
This study was designed to assess current PBDE body burdens and identify residential sources of exposure among 29 men and 15 women in 38 households.
Portable X-ray fluorescence (XRF) analyzers were used to measure bromine levels in upholstered furnishings, bedding, vehicle interiors, and electronic devices. Vacuum cleaner contents, indoor air samples, and blood sera were analyzed for PBDE congeners using conventional gas chromatograph methods.
Bromine levels varied widely within similar household items. The greatest range for upholstered items was found among vehicle seat cushions (7-30,600 ppm). For electronic devices, television sets ranged from 4 ppm to 128,300 ppm. Based on mixed effects modeling, adjusting for couple households, the bromine content in the participants' sleeping pillows and primary vehicle seat cushions were the strongest predictors of log lipid-adjusted blood serum PBDE concentrations (p-values = 0.005 and 0.03, respectively). The total pentaBDE congener levels found in dust samples and in passive air samples were not significant predictors of blood sera levels.
This study demonstrates the usefulness of the portable XRF analyzer in identifying household items that may contribute to human exposure to PBDEs.
Uptake studies have shown that chickens foraging on soils contaminated with environmental pollutants accumulate these compounds into their eggs. Home-produced eggs thereby show higher contamination levels than commercially produced eggs. It was the aim of this study to identify the major source of two environmental pollutants in home-produced eggs, i.e. dioxins and lead, to formulate preventive measures to reduce the contamination levels of such eggs, and to assess the feasibility of the formulated measures in terms of the perception and behavior of private egg producers towards such measures. The major source of dioxins and lead in eggs, i.e. the soil, was identified by transfer calculations of the pollutants from the feed and soil towards eggs. Preventive measures to reduce soil intake or geophagy and hence egg contamination levels, were formulated and their feasibility evaluated through interviews with private chicken owners. The results show that a paved surface inside the henhouse, an indoor feeding place and providing a sufficient surface area per chicken were considered the most appropriate in terms of feasibility and willingness to apply the measures by the private chicken owners. To enhance the effect of the measures, a combination of measures supported and promoted at policy level is considered as a good strategy to reduce contamination levels in home-produced eggs.
Brominated flame retardants (BFRs) are a group of compounds that have received much attention recently due to their similarity with "old" classes of organohalogenated compounds such as polychlorinated biphenyls (PCBs), in terms of their fate, stability in the environment and accumulation in humans and wildlife. Toxic effects, including teratogenicity, carcinogenicity and neurotoxicity, have been observed for some BFR congeners, in particular the brominated diphenyl ethers (BDEs). This concise review focuses on the potency of BFRs and to disrupt endocrine systems, and attempts to answer the question whether or not BFRs are endocrine disruptors. Evidence is provided on the disruption of the thyroid hormone system by BFRs, with particular emphasis on the BDEs, as most recent data is available on this class of flame retardants. Similar to the hydroxylated PCBs, in vitro mechanistic studies as well as animal experiments have demonstrated the effects of BDEs on thyroid hormone transport and metabolism. An overview of possible effects of BFRs on the estrogen system is also provided. Research gaps are outlined, as well as ongoing and future studies in the European community aimed at contributing to comprehensive risk assessments based on the endocrine-disrupting effects of BFRs.
Polybrominated diphenyl ethers (PBDEs) were listed in the Stockholm Convention as POPs because of their bio-accumulative, long-range and toxicity characteristics. Therefore, these should be managed and assessed by Parties of the convention in an environmentally sound manner. This present study assessed the status of PBDEs contamination at e-waste dumpsites in Lagos, Nigeria. Soil and sediment samples were collected from 3 e-waste dumpsites and water samples were collected from rain water ponds located within the e-waste dumpsites vicinities and control sites over a period of two years. The concentrations of ∑7PBDEs in soils from the e-waste dumpsites at 0–15 cm depth for the first and second year ranged from 141 to 302 ngg⁻¹ dry weight, respectively while that of the control soils was 13.2–27.2ngg⁻¹ dry weight. These high concentrations may be attributed to the fact that open burning of electronic waste was the regular method of reducing the volume of e-waste at the sites. PBDE levels across the soil profile from 0 to 45 cm depth showed a gradual increase in PBDEs accumulation in the topsoil and migration into the sub-soil over the period of 2 years, but with no significant difference (p-value = 0.89). Sediments and water from the rain water ponds around the dumpsites were found to be contaminated by PBDEs with levels ranging from 51.4 to 85.8ngg⁻¹ and 14.4 to 27.4ngg⁻¹, respectively, while levels in control for sediment and water are 11.5ngg⁻¹ and 2.43ngg⁻¹respectively.These, however indicates that there was significance difference between the PBDEs levels in water and sediment from the study sites with those of their respective controls (p-value for water was 0.01, while that for sediment was 0.03).The levels of PBDEs in this study sites were higher than those of the respective control. The range of PBDEs in e-waste dumpsites was comparable to those reported in USA and Europe but lower than those from China. Environmental samples from the e-waste dumpsites in Lagos were contaminated with PBDEs, there is therefore the need for proper disposal methods for end-of-life products especially those containing PBDEs in Nigeria.
Persistent organic pollutants (POPs) including PCDD/Fs, PCBs and organochlorine pesticides (OCPs) are among the most important and hazardous pollutants of soil. Food producing animals such as chicken, beef, sheep and goats can take up soil while grazing or living outdoors (free-range) and this can result in contamination.
In recent decades, large quantities of brominated flame retardants such as polybrominated diphenyl ethers (PBDEs), short-chain chlorinated paraffins (SCCPs) and per- and polyfluorinated alkylated substances (PFAS) have been produced and released into the environment and this has resulted in widespread contamination of soils and other environmental matrices. These POPs also bioaccumulate and can contaminate food of animal origin resulting in indirect exposure of humans.
Recent assessments of chicken and beef have shown that surprisingly low concentrations of PCBs and PCDD/Fs in soil can result in exceedances of regulatory limits in food. Soil contamination limits have been established in a number of countries for PCDD/Fs but it has been shown that the contamination levels which result in regulatory limits in food (the maximum levels in the European Union) being exceeded, are below all the existing soil regulatory limits. ‘Safe’ soil levels are exceeded in many areas around emission sources of PCDD/Fs and PCBs. On the other hand, PCDD/F and dioxin-like PCB levels in soil in rural areas, without a contamination source, are normally safe for food producing animals housed outdoors resulting in healthy food (e.g. meat, eggs, milk).
For the majority of POPs (e.g. PBDEs, PFOS, PFOA, SCCP) no regulatory limits in soils exist.
There is, therefore, an urgent need to develop appropriate and protective soil standards minimising human exposure from food producing animals housed outdoors. Furthermore, there is an urgent need to eliminate POPs pollution sources for soils and to control, secure and remediate contaminated sites and reservoirs, in order to reduce exposure and guarantee food safety.
Polybrominated diphenyl ethers are non-reactive flame retardants listed among the persistent organic pollutants. This study assesses the levels and health risk of PBDEs in foods commonly consumed by the adult population in Southwest Nigeria. Eight different food categories were collected and extracted using standard QuEChERS protocol prior to analysis by gas chromatography with micro electron capture detector. Aquatic foods had the highest maximum concentration of the eight PBDEs congeners, 748 pg/g; followed by 80.3 pg/g and 54.9 pg/g in edible oil and meat products, respectively. Dairy products had the lowest concentration (0.46 pg/g). The estimated average dietary intake of PBDEs by an adult was 131 pg/kg bw/day. Based on the levels of PBDEs found in common foods consumed by the adult population in Southwest Nigeria, there is unlikely to be a health risk. However, there is a need to investigate the dietary intake of PBDEs in other food categories, especially by vulnerable groups, such as children and the elderly.
Polybrominated diphenyl ethers (PBDEs) are flame retardants used in a variety of consumer products, which have become ubiquitous environmental contaminants. Concentrations of PBDEs are particularly high in breast milk, resulting in high exposure of infants; for toddlers, dust has been estimated to account for a large percentage of exposure. PBDEs can also cross the placenta, as they have been detected in fetal blood and liver. Tetra-, penta-, and hexa-BDEs are most commonly present in human tissues. The current greatest concern for potential adverse effects of PBDEs relates to their developmental neurotoxicity, particularly in the domains of locomotor activity and cognition. Alterations in circulating thyroid hormone homeostasis and direct effects of PBDEs on the developing brain may represent underlying mechanisms.
As consumer products treated with polybrominated diphenyl ethers (PBDEs) reach the end of their life cycle, they often are discarded into solid waste facilities, offering a potential reservoir for exposure. The likelihood of exposures to PBDEs by residents living near those sites rarely has been explored. This study collected blood samples from 923 female participants in the California Teachers Study in 2011-2013 and examined the association between participants' residential proximity to solid waste facilities with potential release of PBDEs and serum levels of three congeners (BDE-47, BDE-100 and BDE-153). General linear regression analysis was used to examine the association, adjusting for age, race, body mass index, neighborhood socioeconomic status and urban residency. Compared to participants living >10 km from any selected site, those living within 2 km had 45% higher BDE-47 (95% CI: 5-100%) and BDE-100 (95% CI: 0-109%) levels, and those living between 2-10 km had 35% higher BDE-47 (95% CI: 0-82%) and 29% higher BDE-100 (95% CI: -9 to 82%) levels. No associations were found for BDE-153. Living close to some solid waste sites may be related to higher serum BDE-47 and BDE-100 levels. Studies with comprehensive exposure assessments are needed to confirm these initial observations.
Home produced eggs from 62 addresses in the Netherlands were investigated for the levels of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs), both dioxin-like (dl) and non-dioxin-like (ndl). Compared to commercial eggs, levels were relatively high with a median of 4.6 pg TEQ g(-1) fat for the sum of PCDD/Fs and dl-PCBs, and a highest level of 18.9 pg TEQ g(-1) fat. A number of samples showed clearly elevated ndl-PCB levels with a median of 13 ng g(-1) fat and a highest level of 80 ng g(-1) fat. There were no clear regional differences, even though part of the samples were derived from the rather industrial Rotterdam/Rijnmond area. Based on the congener patterns, former backyard burning of waste seems the most likely source for most eggs, with two exceptions where other sources contributed to the contamination. Similar is true for the ndl-PCBs. The study shows that average levels are about ten-fold higher than commercial eggs and may substantially contribute to the intake of PCDD/Fs and dl-PCBs by consumers. Intervention measures to reduce the intake of these contaminants by laying hens are advised.
EFSA was asked by the European Commission to deliver a scientific opinion on polybrominated diphenyl ethers (PBDEs) in food. PBDEs are additive flame retardants which are applied in plastics, textiles, electronic castings and circuitry. PBDEs are ubiquitously present in the environment and likewise in biota and in food and feed. Data from the analysis of 19 PBDE congeners in 3,971 food samples were provided to EFSA by 11 European countries. Eight congeners were considered by the Panel on Contaminants in the Food Chain (CONTAM Panel) to be of primary interest: BDE-28,-47,-99,-100,-153,-154,-183 and-209. The highest dietary exposure is to BDE-47 and-209. Toxicity studies were carried out with technical PBDE mixtures or individual congeners. Main targets were the liver, thyroid hormone homeostasis and the reproductive and nervous system. PBDEs cause DNA damage through the induction of reactive oxygen species. The Panel identified effects on neurodevelopment as the critical endpoint, and derived benchmark doses (BMDs) and their corresponding lower 95 % confidence limit for a benchmark response of 10 %, BMDL 10 s, for a number of PBDE congeners: BDE-47, 309 μg/kg b.w.; BDE-99, 12 μg/kg b.w.; BDE-153, 83 μg/kg b.w.; BDE-209, 1,700 μg/kg b.w. Due to the limitations and uncertainties in the current database, the Panel concluded that it was inappropriate to use these BMDLs to establish health based guidance values, and instead used a margin of exposure (MOE) approach for the health risk assessment. Since elimination characteristics of PBDE congeners in animals and humans differ considerably, the Panel used the body burden as starting point for the MOE approach. The CONTAM Panel concluded that for BDE-47,-153 and-209 current dietary exposure in the EU does not raise a health concern. For BDE-99 there is a potential health concern with respect to current dietary exposure. for the preparatory work on this scientific opinion and the hearing experts: Bas Bokkers and Catherine Viguié, and EFSA staff: Alessandro Carletti, Gina Cioacata, Luisa Ramos Bordajandi and Elena Scaravelli for the support provided to this scientific opinion. The CONTAM Panel acknowledges all the European countries that provided PBDEs occurrence data in food and supported the consumption data collection for the Comprehensive European Food Consumption Database.
This study investigated the material/substance flow of polybrominated diphenyl ethers listed in the Stockholm Convention (SC) as persistent organic pollutant (POP-PBDEs) in the most relevant plastic fractions in Nigeria. Considering the prohibition of production and the use of POP-PBDEs and knowing that these pollutants are still contained in electrical and electronic equipment (EEE) and associated wastes (WEEE), it is necessary to determine their flows, especially in developing countries with limited end-of-life management. Following the inventory approach of the SC Guidance and utilizing the existing national e-waste inventory together with monitoring data, a material/substance flow analysis was conducted using the STAN tool. Within the period of 2000 to 2010, the total import for EEE/WEEE in Category 3 and 4 was approximately 8 million tonnes (Mt) containing approximately 2.4 Mt of polymers. For the inventory year 2010, it was estimated that from these polymers, about 0.8 Mt was still in stock and 1.6 Mt has reached the end-of-life. It was also estimated that approximately 1.1 Mt has ended in dumpsites, 0.3 Mt was burned in the open, and 0.2 Mt was recycled. In the plastic fractions, 1,270 t of POP-PBDEs was contained with about 370 t still in use/stock and approximately 900 t has entered the end-of-life phase. All three major end-of-life treatments result in environmental pollution with associated exposure risk. The implementation of the Stockholm Convention represents an important opportunity to improve this management situation in Nigeria and other developing countries.
The bioaccumulation of polychlorinated biphenyls, dibenzo-p-dioxins, dibenzofurans, and hexachlorobenzene in an air−plant/soil−cow−human food chain was examined using field data collected in southern Germany. The fugacity of many compounds was similar in air, soil, and plants, suggesting near-equilibrium partitioning with somewhat higher fugacities in cows' milk indicative of moderate biomagnification. However, the fugacities of the more involatile, hydrophobic compounds decreased by up to several orders of magnitude from air to plants to cows' milk. This phenomenon, termed biodilution, can be explained by the kinetically limited uptake of less volatile compounds in plants and the reduced absorption of very hydrophobic compounds in cows. Biodilution due to metabolism of certain compounds in cows was also observed. Strong biomagnification was observed in humans as indicated by 20−50 times higher fugacities in human milk compared to cows' milk.
Brominated flame retardants (BFRs), including polybrominated diphenyl ethers (PBDEs), 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenyl ethane (DBDPE), and polybrominated biphenyls (PBBs) were found in children’s toys purchased from South China. The median BFR concentrations in the hard plastic toys were 53 000, 5540 ng/g, 101.1 ng/g, and 27.9 ng/g, for total PBDEs, DBDPE, BTBPE, and PBBs, respectively, which were notably higher than values in other toys. The PBDE concentrations were below the threshold limit (1000 ppm) required by the European Commission’s Restriction of Hazardous Substances (RoHS) and Waste Electrical and Electronic Equipment (WEEE) directives in all of the toys, except for one hard plastic toy with a total PBDE concentration of 5 344 000 ng/g. The BFR profiles in the toys were consistent with the patterns of their current production and consumption in China, where PBDEs, specifically decaBDE product, were the dominant BFR, followed by the emerging DBDPE. The relatively high concentrations of octa- and nonaBDEs in the foam toys and the results of principal component analysis (PCA) may suggest the decomposition of highly brominated BDEs during the manufacturing processes of the toys. Daily total PBDE exposures associated with toys via inhalation, mouthing, dermal contact, and oral ingestion ranged from 82.6 to 8992 pg/kg bw-day for children of 3 months to 14 years of age. Higher exposures, predominantly contributed through the mouthing pathway, were observed for infants and toddlers than for the other subgroups. In most cases, children’s BFR exposure via the toys likely accounts for a small proportion of their daily BFR exposure, and the hazard quotients for noncancer risk evaluation were far below 1. To the author’s knowledge, this is the first study to examine the concentrations of BFRs in toys, and the potential exposures to children.
Brominated dioxins (PBDD/Fs) and 17 polybrominated diphenylether (PBDE) congeners including BDE-209 were analysed in 100 composite samples of commonly consumed foods of animal origin, prepared from ten to 40 individual subsamples of each type. These included 30 samples of milk from farms; eggs from chickens; fat from cows, pigs, sheep, and poultry; and liver from cows, pigs, sheep, horses, and poultry. The ISO 17025-accredited analytical methodology used, follows similar guidelines as given for chlorinated dioxins and polychlorinated biphenyls (PCBs) in European Commission Directive 2002/69/EC. Apart from some samples of milk, PBDD/Fs and PBDEs were detected in all food types. Concentrations ranged from 0.31 µg kg Σ17 PBDEs for a sample of milk to 37.5 µg kg Σ17 PBDEs for a sample of liver. The corresponding range for the PBDD/F toxicity (computed using analogous PCDD/F toxic equivalency factors (TEFs)) was 0.09 ng TEQ kg to approximately 3.5 ng TEQ kg. The detection of these compounds, in particular PBDD/Fs, is consistent with the increased use and disposal of brominated organic compounds.
Three regulated halogenated flame retardants (HFRs), i.e., polybrominated diphenyl ethers (PBDEs), polybrominated biphenyls (PBBs) and hexabromocyclododecanes (HBCDs), and several alternative HFRs (AHFRs) including Dechlorane Plus (DP), decabromodiphenyl ethane (DBDPE), and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), were investigated in the home-produced eggs from three recycling sites and a reference site in an electronic waste (e-waste) recycling region, South China. Mean levels of HFRs in eggs from the recycling sites ranged 2640-14100, 700-1620, 44-350, and 720-3920 ng/g lipid weight for ∑PBDEs, ∑PBBs, ∑HBCDs, and ∑AHFRs, respectively, which were one to two orders of magnitude higher than those examined in the reference site. PBDEs were the predominant HFR in those eggs, with contributions >50% to the total HFRs; followed by PBBs and the AHFRs (contributing 14-22% in average). The α-HBCD was the predominant diastereoisomers of HBCDs, with preferential enrichment of the (-)-enantiomer in most of the eggs; but no significant stereoselective enrichment of the DP isomers was observed in these eggs. The average estimated daily intakes (EDIs) of PBDEs, PBBs, HBCDs, and the AHFRs via eggs from the recycling sites ranged 4200-20000, 1120-2440, 80-490, and 970-4530 ng/day, respectively, which were one to two orders of magnitude higher than those reported from other parts of the world. The potential adverse effects of these HFRs to human health in the e-waste sites should be further investigated. This is the first report on the isomer compositions of DP and the chiral signatures of HBCDs in hen eggs.
Atmospheric concentrations of halogenated flame retardants (FRs) were monitored for approximately one year at two remote stations, namely Nam Co on the Tibetan Plateau and Alert in the Canadian High Arctic. BDE-47 and 99 were the dominant polybrominated diphenyl ether (PBDE) congeners at both sites. Atmospheric PBDE concentrations in Nam Co were generally lower than those at Alert. While significant seasonal variations were observed for PBDEs at Alert, the FR concentrations at Nam Co showed no significant seasonality, even though air masses originated from distinctly different regions during different seasons. This suggests that FRs in Tibet do not have regional sources, but are reflective of truly global background contamination. Three new FRs, namely 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), 2-ethyl-1-hexyl-2,3,4,5-tetrabromobenzoate (EHTeBB) and bis(2-ethyl-1-hexyl)tetrabromophthalate (TBPH) were detected at relatively high concentrations at both sites. This is the first report of these FRs in the remote global atmosphere and suggests significant potential for long-range atmospheric transport.
Recent studies show that PCB (polychlorinated biphenyl) air concentrations remain surprisingly high in parts of Africa and Asia. These are regions where PCBs were never extensively used, but which are implicated as recipients of obsolete products and wastes containing PCBs and other industrial organic contaminants, such as halogenated flame retardants (HFRs). We hypothesize that there may be different trends in emissions across the globe, whereby emissions of some industrial organic contaminants may be decreasing faster in former use regions (due to emission reductions combined with uncontrolled export), at the expense of regions receiving these substances as obsolete products and wastes. We conclude that the potential for detrimental effects on the environment and human health due to long-range transport by air, water, or wastes should be of equal concern when managing and regulating industrial organic contaminants. This calls for a better integration of life-cycle approaches in the management and regulation of industrial organic contaminants in order to protect environmental and human health on a global scale. Yet, little remains known about the amounts of industrial organic contaminants exported outside former use regions as different types of wastes because of the often illicit nature of these operations.
Polybrominated diphenyl ethers (PBDEs) are flame retardants that are commonly found in commercial and household products. These compounds are considered persistent organic pollutants. In this study, we used 4,4'-dibromodiphenyl ether (BDE-15) as a model compound to elucidate the sorption and desorption behavior of PBDEs in soils. The organic carbon-normalized sorption coefficient (K(OC)) of BDE-15 was more than three times higher for humin than for bulk soils. However, pronounced desorption hysteresis was obtained mainly for bulk soils. For humin, increasing concentration of sorbed BDE-15 resulted in decreased desorption. Our data illustrate that BDE-15 and probably other PBDEs exhibit high sorption affinity to soils. Moreover, sorption is irreversible and thus PBDEs can potentially accumulate in the topsoil layer. We also suggest that although humin is probably a major sorbent for PBDEs in soils, other humic materials are also responsible for their sequestration.
With the phase-out of PentaBDE in 2004, alternative flame retardants are being used in polyurethane foam to meet flammability standards. However, insufficient information is available on the identity of the flame retardants currently in use. Baby products containing polyurethane foam must meet California state furniture flammability standards, which likely affects the use of flame retardants in baby products throughout the U.S. However, it is unclear which products contain flame retardants and at what concentrations. In this study we surveyed baby products containing polyurethane foam to investigate how often flame retardants were used in these products. Information on when the products were purchased and whether they contained a label indicating that the product meets requirements for a California flammability standard were recorded. When possible, we identified the flame retardants being used and their concentrations in the foam. Foam samples collected from 101 commonly used baby products were analyzed. Eighty samples contained an identifiable flame retardant additive, and all but one of these was either chlorinated or brominated. The most common flame retardant detected was tris(1,3-dichloroisopropyl) phosphate (TDCPP; detection frequency 36%), followed by components typically found in the Firemaster550 commercial mixture (detection frequency 17%). Five samples contained PBDE congeners commonly associated with PentaBDE, suggesting products with PentaBDE are still in-use. Two chlorinated organophosphate flame retardants (OPFRs) not previously documented in the environment were also identified, one of which is commercially sold as V6 (detection frequency 15%) and contains tris(2-chloroethyl) phosphate (TCEP) as an impurity. As an addition to this study, we used a portable X-ray fluorescence (XRF) analyzer to estimate the bromine and chlorine content of the foam and investigate whether XRF is a useful method for predicting the presence of halogenated flame retardant additives in these products. A significant correlation was observed for bromine; however, there was no significant relationship observed for chlorine. To the authors knowledge, this is the first study to report on flame retardants in baby products. In addition, we have identified two chlorinated OPFRs not previously documented in the environment or in consumer products. Based on exposure estimates conducted by the Consumer Product Safety Commission (CPSC), we predict that infants may receive greater exposure to TDCPP from these products compared to the average child or adult from upholstered furniture, all of which are higher than acceptable daily intake levels of TDCPP set by the CPSC. Future studies are therefore warranted to specifically measure infants exposure to these flame retardants from intimate contact with these products and to determine if there are any associated health concerns.
The first investigation into PBDE levels in food produced from flood-prone land on industrial river catchments was conducted. In August 2008 samples of cows' milk, along with grass and soil were taken from 5 pairs of flood-prone and control farms on the River Trent (Central UK). The sum of 7 BDE congeners (28, 47, 99, 100, 153, 154, and 183) was calculated. Higher PBDE levels occurred in soil on flood-prone compared to control farms (median 770 vs 280 ng/kg dry weight). These higher levels were not reflected in the grass samples indicating that PBDE contamination on soils is not transferred efficiently to grass. This observation alongside the fact that cows on flood-prone farms spend time on non-flood-prone land and are fed substantial quantities of commercial feed are reasons why higher PBDE levels were not found in milk from flood-prone farms (median 300 vs 250 ng/kg fat weight). Similar BDE47/BDE99 ratios were observed in soil and grass samples compared to the PBDE product commonly used in the UK, indicating few differences in source-pathway transfer efficiencies between congeners. The BDE47/BDE99 ratio in the milk samples was greater than those in the grass and feed indicating differential food to milk transfer efficiencies between congeners.
The levels and distributions of polybrominated diphenyl ethers (PBDEs) in chicken tissues from an electronic waste (e-waste) recycling area in southeast China were investigated. Human dietary intake by local residents via chicken muscle and eggs was estimated. The mean PBDEs concentrations in tissues ranged from 15.2 to 3138.1 ng/g lipid weight (lw) and in egg the concentration was 563.5 ng/g lw. The results showed that the level of total PBDEs (sigmaPBDEs) in the chicken tissue was 2-3 orders of magnitude higher than those reported in the literature. The large difference of sigmaPBDEs concentrations between tissues confirmed that the distribution of PBDEs in tissues depend on tissue-specificity rather than the "lipid-compartment". BDE-209 was the predominant congener (82.5%-94.7% of sigmaPBDEs) in all chicken tissues except in brain (34.7% of sigmaPBDEs), which indicated that deca-BDE (the major commercial PBDE formulation comprising 65%-70% of total production) was major pollution source in this area and could be bioaccumulated in terrestrial animals. The dietary PBDEs intake of the local residents from chicken muscle and egg, assuming only local bred chickens and eggs were consumed, ranged from 2.2 to 22.5 ng/(day x kg body weight (bw)) with a mean value of 13.5 ng/(day x kg bw), which was one order of magnitude higher than the value reported in previous studies for consumption of all foodstuffs.
The landfilling and dumping of persistent organic pollutants (POPs) and other persistent hazardous compounds, such as polychlorinated biphenyls (PCBs), hexachlorocyclohaxane (HCH), polybrominated diphenylether (PBDEs) or perfluorooctane sulfonic acid (PFOS) can have significant adverse environmental consequences. This paper reviews past experiences with such disposal practices and highlights their unsustainability due to the risks of contamination of ecosystems, the food chain, together with ground and drinking water supplies.
This paper discusses the dioxin TEQ levels as determined by the chemically activated luciferase gene expression assay (CALUX) and by HRGC-HRMS in eggs, soils, faeces and kitchen waste samples obtained in the CONTEGG study. The samples were collected in each Belgian province at private homes and in small gardens where chickens are held. The CALUX levels for eggs sampled in autumn were higher than the levels in eggs obtained at the same locations in spring (median values of 5.86 and 4.08 pg CALUX TEQ/g fat, respectively). The total WHO-TEQ levels in eggs, determined by HRGC-HRMS, ranged from 3.29 to 95.35 pg TEQ/g fat in autumn and from 1.50 to 64.79 pg TEQ/g fat in spring. In the soils on which the chickens forage, levels of 2.51-11.35 pg I-TEQ/g in autumn and 2.00-7.86 pg I-TEQ/g in spring were found. The congener pattern of PCDD/Fs in the eggs, soils and faeces was dominated by OCDD, in addition to 1,2,3,4,6,7,8-HeptaCDD, OCDF and 1,2,3,4,6,7,8-HeptaCDF. The predominant dioxin-like PCBs were PCB118, PCB 105 and PCB 156. The dioxin-like PCBs contributed on average 47%, 14% and 20% to the total WHO-TEQ in eggs, soils and faeces, respectively. Kitchen waste samples were very low-contaminated with dioxin-like compounds. The present results showed a good agreement between egg and soil TEQ levels for PCDD/Fs but not for dioxin-like PCBs. This study showed that current soil levels found in some private gardens do not lead to egg levels below the current EU maximal level of 6 pg total TEQ/g fat for dioxins and dioxin-like PCBs. The consumers of the analysed eggs attained 5-79% of the tolerable weekly intake (TWI) of 14 pg TEQ/kg bw for dioxins and dioxin-like PCBs by exposure to their home-produced eggs only.
The level of polychlorinated biphenyls (PCB) and persistent organochlorinated pesticides (OC) in home-produced eggs was investigated in Belgium. The concentration of dichlorodiphenytrichloroethane (DDT) is above the norm for 17% of the eggs collected during the spring on 58 different locations. For PCB, aldrin, dieldrin, and chlordane, 3-5% of the samples are above the norm too. These levels are surprisingly high for compounds banned for about 30 years. Higher concentrations in home-produced eggs are expected compared to battery eggs because of contact with the environment and especially the soil. For ten selected locations, the concentration in soils, excreta and feed was measured, but no simple correlation between egg and feed or soil level could be established. Hexachlorohexane, endosulfan, endrin, methoxychlor and nitrofen were not detected in any sample.
This overview paper describes a study conducted for the Belgian Federal Public Service of Health, Food Chain Safety and Environment during 2006-2007. Home-produced eggs from Belgian private owners of hens were included in a large study aiming to determine concentration levels of various environmental contaminants. By means of the analyses of soil samples and of kitchen waste samples, obtained from the same locations, an investigation towards the possible sources of contaminants was possible. Eggs, soils, faeces and kitchen waste samples were checked for the presence of dioxins, PCBs (including dioxin-like PCBs), organochlorine pesticides, trace elements, PAHs, brominated flame retardants and mycotoxins. The study design, sampling methodology and primary conclusions of the study are given. It was found that in some cases dioxin-like compounds were present at levels that are of concern for the health of the egg consumers. Therefore, measures to limit their contamination in eggs, produced by hens of private owners, were proposed and deserve further attention.
The purpose of this study was to evaluate the levels of arsenic, cadmium, lead, copper and zinc in home-produced eggs, soils and kitchen waste samples of private chicken owners in Belgium, and to determine spatiotemporal differences in trace element contents in eggs. Eggs were sampled in all provinces of Belgium in autumn 2006 and spring 2007. A total number of 59 private chicken owners participated in the study. Trace elements were determined by inductively coupled plasma-mass spectrometry except for mercury, which was determined by atomic absorption of mercury vapour. The mean fresh weight concentrations in eggs in autumn and spring respectively were <8.0 and <8.0 microg/kg for arsenic, 0.5 and <0.5 microg/kg for cadmium, 116 and 74 microg/kg for lead, 0.43 and 0.52 mg/kg for copper, 20.3 and 19.2 mg/kg for zinc, and 3.15 and 4.44 microg/kg for mercury. Analysis of variance determined significant differences in some trace element concentrations in eggs among seasons and regions in Belgium. Average concentrations of arsenic, cadmium and mercury corresponded well with values measured in other countries, while copper and zinc concentrations were within the same order of magnitude as in other countries. Average lead concentrations were high compared to concentrations in eggs from other countries and correlated well with lead concentrations in soil, indicating that the soil is an important source. Other sources of trace elements in eggs might be home-grown vegetables and forage (grass and herbs), and indirectly, air pollution.
The extent and the sources of contamination with brominated flame retardants (BFRs), such as polybrominated diphenyl ethers (PBDEs) and hexabromocyclododecane (HBCD), in home-produced eggs from free-foraging chicken of Belgian private owners were investigated. Various factors, such as seasonal variability, exposure of chickens through diet (kitchen waste) and soil, and elimination of BFRs through eggs and faeces were assessed. PBDEs were more important than HBCD in terms of concentrations and detection frequency. Concentrations of PBDEs and HBCD in Belgian home-produced eggs were relatively low and comparable with reported levels from other European countries and the US. The concentrations of PBDEs (sum of 13 congeners, including BDE 209) ranged between not detected and 32 ng/g lipid weight (lw), with medians of 3.0 and <2.0 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively. When present, BDE 209 was the major PBDE congener (45% of sum PBDEs). When BDE 209 was not detected, the PBDE profile was composed of PentaBDE (BDE 99 and BDE 47), with, in some cases, higher contribution of OctaBDE (BDE 183 and BDE 153). HBCD was also detected (<0.4 and 2.9 ng/g lw for the autumn 2006 and spring 2007 campaigns, respectively), but at lower detection frequency. The highest HBCD value was 62 ng/g lw. The similarity between profiles and seasonal variations in the concentrations of BFRs in soil and eggs indicate that soil is an important source, but not the sole source, for eggs laid by free-foraging chicken. The contamination of eggs with PBDEs and HBCD appears to be of low concern for public health and the contribution of eggs to the total daily intake of PBDEs appears to be limited (10% for chicken owners and 5% for the average Belgian consumer).
The objective of this review is to provide an overview of recent studies demonstrating the endocrine disrupting (ED) effects of brominated flame retardants (BFRs), while highlighting interesting data presented at the recent international BFR workshop in Amsterdam in April, 2007. A review written in 2002 was used as a starting point and about 60 publications published since 2003 were reviewed. New insights into the in vivo effects of BFRs on thyroid hormone, estrogen and androgen pathways in both mammalian and non-mammalian models are provided, and novel (in vitro) findings on the mechanisms underlying ED effects are highlighted. Special attention is also given to reports on neurotoxicological effects at relatively low doses of BFRs, although an endocrine-related mechanism is disputable. Convincing evidence has been published showing that BFRs and importantly, BFR metabolites, have the potential to disrupt endocrine systems at multiple target sites. While some studies suggest a wide margin of safety between effect concentrations in rodent models and levels encountered in humans and the environment, other studies demonstrate that exposure to low doses relevant for humans and wildlife at critical time points in development can result in profound effects on both endocrine pathways and (neuro)development.
Chickens were used as a model for foraging animals to examine the bioavailability of all 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDFs) from soil. Three groups of chickens were exposed through their diet to soil contaminated with PCDD/PCDFs at less than 0.5 pg/g I-TEQ (control group), 42 pg/g I-TEQ (low exposure group), and 460 pg/g I-TEQs (high exposure group). Eggs, tissues, feces and feed were analysed throughout the exposure and depuration period. Daily intake was estimated at 2.5 ng/kg-day for the high and 0.3 ng/kg-day for the low exposure groups. Bioavailability was chlorination-dependent ranging from 80% for tetrachlorinated to less than 10% for octachlorinated congeners. During exposure, tissue distribution was congener-dependent with 5-30% of the intake excreted in the eggs, 7-54% deposited in the adipose and less than 1% present in the liver. On a fat weight basis, the highest concentrations were observed in the liver, implying that mechanisms other than lipid solubility operate in that tissue. Bioconcentration factors and elimination half-lives were also congener- and tissue-dependent. Results from this study indicate that animals foraging on soil contaminated at low ppt PCDD/PCDF levels may bioaccumulate these compounds to unacceptable levels.
This paper uses data from a detailed 4 month PCB mass balance study on lactating cows fed a naturally contaminated background diet to quantify the metabolism and body-burdens of a range of PCB congeners. Dietary intake fluxes and milk and faecal output fluxes reported previously are combined with subcutaneous fat and blood PCB concentrations and with data from tissue/organ samples from a slaughtered animal to estimate the degree of metabolism within the cow. A total body burden is derived, showing that fat deposits account for approximately 98% of total PCB present in the lactating cow. The daily intake through feed (ng day-1) accounted for between 0.9 and 1.5% of the total body burden for persistent congeners (e.g. PCB 153) and up to 43% for those congeners which are readily metabolised (e.g. PCB 52). Detailed balances for a range of tri- to octa-chlorinated PCBs are presented and clearly demonstrate that many congeners are metabolised effectively by lactating dairy cows (e.g. PCB 149) whilst others are efficiently transferred to human dairy food products. An approach to predicting the degree of metabolism for individual PCB congeners is presented which gives good agreement with observations.
The presence of brominated flame retardant (BFR) chemicals, and particularly polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane (HBCD), has become of increasing concern to scientists over the past decade. Environmental studies conducted primarily in Europe, Japan and North America indicate that these chemicals are ubiquitous in sediment and biota. The levels of PBDEs seem to be increasing, and several trends, including in humans, indicate that this increase may be rapid. The occurrence of high concentrations of certain PBDE isomers may be sufficient to elicit adverse effects in some wildlife. There is also concern that levels could cause adverse effects in sensitive human populations such as young children, indigenous peoples, and fish consumers. However, our knowledge about these chemicals, their sources, environmental behavior, and toxicity is limited, making risk assessment difficult. In this paper, the current state of knowledge is reviewed and areas for further research recommended to improve future monitoring and risk assessment efforts.
Brominated flame retardants (BFRs) are ubiquitous industrial chemicals, and many of them are produced in large volumes. Due to this fact, several BFRs are found in quantifiable levels in wildlife, as well as in humans. However, we are still lacking information on the effects of BFR in wildlife and, especially, in man. This review summarises the biological effects of polybrominated diphenyl ethers (PBDEs), tetrabromobisphenol A (TBBPA) and derivates, hexabromocyclododecane (HBCD) and polybrominated biphenyls (PBBs), however excluding other aspects such as environmental levels. These BFR groups were selected because of a large volume production (PBDEs, TBBPA and derivates), and availability of some toxicity data in spite of much lower production volumes (HBCD and PBBs). In addition, the increase in levels of PBDEs in human (breast milk) and wildlife samples during later time made it especially interesting to include this BFR group. PBDES: The commercial PBDE products predominantly consist of so-called penta-, octa- and decabromodiphenyl ether products. Each product consists of a rather narrow range of congeners and is named after the dominating congener as regards the bromination pattern. Generally, the PentaBDEs seem to cause adverse effects at the comparably lowest dose, whereas much higher doses were needed for effects of the DecaBDEs. The critical effects of PentaBDEs are those on neurobehavioural development (from 0.6 mg/kg body weight) and, at somewhat higher dose, thyroid hormone levels in rats and mice, of OctaBDEs on fetal toxicity/teratogenicity in rats and rabbits (from 2 mg/kg body weight), and of DecaBDEs on thyroid, liver and kidney morphology in adult animals (from 80 mg/kg body weight). Carcinogenicity studies, only performed for DecaBDEs, show some effects at very high levels, and IARC (1990) evaluates DecaBDEs not classifiable as to its carcinogenicity to humans. TBBPA: The toxicity of TBBPA in the experimental in vivo studies is suggested to be low. In most reported studies, only doses in g/kg body weight were effective, but at least one study suggested renal effects at around 250 mg/kg body weight. Although difficult to include and interpret in a quantitative risk assessment, the in vitro effects on immunological and thyroid hormones, as well as binding to erythrocytes should be noted. Before a solid standpoint could be reached on TBBPA toxicity additional studies must be performed. This statement is even more valid regarding the TBBPA derivates, where there is an almost complete lack of toxicity data. HBCD: Also in the case of HBCD, relevant toxicity studies are lacking. Based on the present animal studies, a critical effect is seen in the liver and on thyroid hormones (LOAEL 100 mg/kg body weight/day). However, in a recent short paper behavioural effects in mice pups were observed already at 0.9 mg/kg body weight, and behavioural effects may be a sensitive endpoint for HBCD, as well as for other BFRs. PBBS: Due to the Michigan accident in 1973-1974, many toxicity studies on PBBs are available. The critical experimental effects are those on reproduction and carcinogenicity, and a NOAEL of 0.15 mg/kg body weight/day could be suggested based on the cancer effects. In man no unequivocal effects have been observed, although in some studies neurological and musculoskeletal symptoms were suggested. Based on the carcinogenic effects in animals, a human TDI of 0.15 microg/kg body weight has been presented. To conclude, the toxicity data are almost entirely based on experimental models. There are differences among the BFR groups, as well as within these groups, both regarding type of toxic effect and at what dose it appears. As BFRs will continue to appear both in industrial applications and, even if the production has ceased, in our environment, there is a continued need for effects studies on BFRs.
Analytical methods for the determination of brominated flame retardants (BFRs), with a special emphasis on polybrominated diphenyl ethers (PBDEs) are reviewed. A number of procedures, which can be applied to the analysis of PBDEs and polybrominated biphenyls (PBBs), and in some cases for hexabromocyclododecane (HBCD), in environmental and human samples are described. Because several BFRs, such as tetrabromobisphenol-A (TBBP-A), BDE 209 and, to some extent, HBCD, may require a different approach, specific advice on their analysis is given separately when needed. Sample pretreatment, extraction, cleanup and fractionation, injection techniques, chromatographic separation, detection methods, quality control and method validation are discussed. For each topic, an overview is given of the current status of the field and recommendations for an appropriate analytical approach are presented.
The widespread use of brominated flame-retarded products in the last two decades has resulted in an increasing presence of bromine in thermal processes such as waste combustion and accidental fires. Brominated and brominated–chlorinated dibenzodioxins and dibenzofurans (PBDDs/PBDFs, PXDDs/PXDFs) are micropollutants of concern arising from such processes. The present review aims to evaluate the relevance of these compound classes in actual thermal processes. Four categories of thermal processes are discussed in this respect according to their potential for PBDD/PBDF and PXDD/PXDF generation: thermal stress, pyrolysis/gasification, insufficient combustion conditions and controlled combustion conditions. Under thermal stress situations, as they may occur in production or recycling processes, PBDDs/PBDFs precursors like polybrominated diphenylethers (PBDE) can have a relevant potential for PBDD/PBDF formation via a simple elimination. Under insufficient combustion conditions as they are present in, e.g. accidental fires and uncontrolled burning as well as gasification/pyrolysis processes, considerable amounts of PBDDs/PBDFs can be formed from BFRs, preferably via the precursor pathway. In contrast, under controlled combustion conditions, BFRs and PBDDs/PBDFs can be destroyed with high efficiency. The relevance of de novo synthesis of PXDDs/PXDFs is discussed for this condition.